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Schematic diagram demonstrating the coupled cryostats and the various components of the magnet system. (a) The two cryostats, connected together on a mounting plate, 170 mm by 65 mm, that can be secured directly onto an optical table. (b) An enlarged view of (a) showing the sample in the center of the magnet coil sitting at the end of a cylindrical sapphire pipe, which is secured to the copper cold finger of the helium flow cryostat using an indium ring and a sealing flange. The sample can be mounted on either side of the sapphire plate. Windows provide direct optical access on either side of the system. (c) A photo showing the magnet with an outer diameter of ∼ 43 mm. A coaxial electrode connected to the mini-coil to deliver up to ∼ 5 kA to the coil generating a peak magnetic field of 30 T.
Source publication
We have developed a mini-coil pulsed magnet system with direct optical access, ideally suited for nonlinear and ultrafast spectroscopy studies of materials in high magnetic fields up to 30 T. The apparatus consists of a small coil in a liquid nitrogen cryostat coupled with a helium flow cryostat to provide sample temperatures down to below 10 K. Di...
Contexts in source publication
Context 1
... magnet system consists of two coupled cryostats, as shown in Fig. 1(a). One cryostat contains a small mag- net coil that must be kept in a bath of liquid nitrogen to cool the coil after each magnet shot. The other cryo- stat is a commercial liquid helium flow cryostat (Cryo Industries, Inc., CFM-1738-102), which is used to cool the sample. A cylindrical sapphire pipe extends from the helium flow ...
Context 2
... Ti:sapphire laser (Clark-MXR, Inc., CPA-2001) centered at 775 nm with 1 kHz repetition rate, 150 fs pulse-width, and pulse energies up to 5 µJ. The excitation beam enters through the window on the helium flow cryostat side to optically excite the sample. The sample sits on a sapphire plate on the helium flow cryostat side (shown opposite in Fig. 1 measurements demonstrated in this work. The spot size of the excitation beam on the sample is ∼500 µm. We use an optical chopper to reduce the repetition rate of the excitation pulses to 50 Hz because the silicon charge- coupled device (CCD) used to measure the emitted light cannot operate as fast as 1 ...
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Citations
... Here, we review magneto-optical studies performed with the Rice Advanced Magnet with Broadband Optics (RAMBO), a unique table-top, mini-coil pulsed magnet system. 18) The RAMBO magnet can generate a magnetic field pulse with a peak field up to 30 T, and the sample cryostat provides temperature control between 12 and 300 K. RAMBO has direct optical access through optical windows, which allows ultrafast optical spectroscopy experiments with minimal pulse broadening. The portability and small footprint of RAMBO permit its convenient incorporation into any optical spectroscopy setup. ...
... Detailed information on the first coil is provided in a previous publication. 18) The second-generation magnet coil is made by winding a 1 mm  1:5 mm AgCu wire around the metal bore. The coil is composed of 13 layers, and each layer consists of 14-15 turns. ...
... The inductance of the coil at 77 K is 411.7 µH, which is close to the previous coil. 18) A pickup coil is wrapped around the sapphire pipe near the sample to measure the generated magnetic field pulse. Figure 1(b) shows a measured temporal profile of a magnetic field pulse with a peak field of AE30 T and a pulse duration of about 4.7 ms. ...
... intermediate angle θ between the y axis and z axis, and a THz pulse whose magnetic field polarizes along the x axis propagates through the crystal to probe the magnon frequencies and magnon-magnon coupling. The external field required to observe sizable magnon-magnon coupling should be as large as 30 T, which was supplied by a unique table-top pulsed magnet [138,360] coupled with a broadband optical cryostat. ...
Recent interest in developing fast spintronic devices and laser-controllable magnetic solids has sparked tremendous experimental and theoretical efforts to understand and manipulate ultrafast dynamics in materials. Studies of spin dynamics in the terahertz (THz) frequency range are particularly important for elucidating microscopic pathways toward novel device functionalities. Here, we review THz phenomena related to spin dynamics in rare-earth orthoferrites, a class of materials promising for antiferromagnetic spintronics. We expand this topic into a description of four key elements. (1) We start by describing THz spectroscopy of spin excitations for probing magnetic phase transitions in thermal equilibrium. While acoustic magnons are useful indicators of spin reorientation transitions, electromagnons that arise from dynamic magnetoelectric couplings serve as a signature of inversion-symmetry-breaking phases at low temperatures. (2) We then review the strong laser driving scenario, where the system is excited far from equilibrium and thereby subject to modifications to the free energy landscape. Microscopic pathways for ultrafast laser manipulation of magnetic order are discussed. (3) Furthermore, we review a variety of protocols to manipulate coherent THz magnons in time and space, which are useful capabilities for antiferromagnetic spintronic applications. (4) Finally, new insights on the connection between dynamic magnetic coupling in condensed matter and the Dicke superradiant phase transition in quantum optics are provided. By presenting a review on an array of THz spin phenomena occurring in a single class of materials, we hope to trigger interdisciplinary efforts that actively seek connections between subfields of spintronics, which will facilitate the invention of new protocols of active spin control and quantum phase engineering.
... Here, we review magneto-optical studies performed with the Rice Advanced Magnet with Broadband Optics (RAMBO), a unique table-top, mini-coil pulsed magnet system. 18) The RAMBO magnet can generate a magnetic field pulse with a peak field up to 30 T, and the sample cryostat provides temperature control between 12 K and 300 K. RAMBO has direct optical access through optical windows, which allows ultrafast optical spectroscopy experiments with minimal pulse broadening. The portability and small footprint of RAMBO permit its convenient incorporation into any optical spectroscopy setup. ...
... Detailed information on the first coil is provided in a previous publication. 18) The second-generation magnet coil is made by winding a 1 mm × 1.5 mm AgCu wire around the metal bore. The coil is composed of 13 layers, and each layer consists of 14-15 turns. ...
... The inductance of the coil at 77 K is 411.7 µH, which is close to the previous coil. 18) A pickup coil is wrapped around the sapphire pipe near the sample to measure the generated magnetic field pulse. Figure 1b shows a measured temporal profile of a magnetic field pulse with a peak field of ±30 T and a pulse duration of about 4.7 ms. ...
Optically probing materials in high magnetic fields can provide enlightening insight into field-modified electronic states and phases, while optically driving materials in high magnetic fields can induce novel nonequilibrium many-body dynamics of spin and charge carriers. While there are high-field magnets compatible with standard optical spectroscopy methods, they are generally bulky and have limited optical access, which prohibit performing state-of-the-art ultrafast and/or nonlinear optical experiments. The Rice Advanced Magnet with Broadband Optics (RAMBO), a unique 30-T pulsed mini-coil magnet system with direct optical access, has enabled previously challenging experiments using femtosecond optical pulses, including time-domain terahertz spectroscopy, in cutting-edge materials placed in strong magnetic fields. Here, we review recent experimental advances made possible by the first-generation RAMBO setup. After summarizing technological aspects of combining optical spectroscopic techniques with the mini-coil magnet, we describe results of magneto-optical studies of a wide variety of materials, providing new insight into the states and dynamics of four types of quasiparticles in solids - excitons, plasmons, magnons, and phonons - in high magnetic fields.
... However, microscopic probes of the lattice, electronic states, and magnetic states, such as neutron scattering, x-ray diffraction, spectroscopy, and resonance techniques are elusive with pulsed high magnetic fields because of the shortage of the accumulation time of the signal. Below 100 T generated with millisecond pulses, there have been great efforts such as x-ray experiments [18], nuclear magnetic resonance [19], teraheltz time-domain spectroscopy (THz-TDS) [20]. However, these microscopic measurements are impossible at above 100 T because 100 T environments are limited to the pulse durations of a few -seconds. ...
We devised a portable system that generates pulsed high magnetic fields up to 77 T with 3 $\mu$s duration. The system employs the single turn coil method, a destructive way of field generation. The system consists of a capacitor of 10.4 $\mu$F, a 30 kV charger, a mono air-gap switch, a triggering system, and a magnet clamp, which weighs less than 1.0 tons in total and is transportable. The system offers opportunities for single-shot experiments at ultrahigh magnetic fields in combinations with novel quantum beams. The single-shot x-ray diffraction experiment using x-ray free-electron laser at 65 T is presented. We comment on the possible update of the system for the generation of 100 T.
... intermediate angle θ between the y axis and z axis, and a THz pulse whose magnetic field polarizes along the x axis propagates through the crystal to probe the magnon frequencies and magnon-magnon coupling. The external field required to observe sizable magnon-magnon coupling should be as large as 30 T, which was supplied by a unique table-top pulsed magnet [138,360] coupled with a broadband optical cryostat. ...
... In THz TDS studies of rare-earth orthoferrites, freeinduction decay signals from precessing spins are measured directly in the time domain, the Fourier transform of which reveal the precessional (magnon) frequency 26 . We combined two unique experimental apparatuses: a table-top, 30 T pulsed magnet 27 and single-shot THz detection 28,29 , illustrated in Fig. 1a. THz pulses were focused onto the samples, and the transmitted THz waveform was detected using a single-shot technique based on a reflective echelon that separates an optical probe pulse into time-delayed beamlets that overlap with the THz waveform in our ZnTe detection crystal 28,29 . ...
... Magnetic fields up to 30 T were generated in the Rice Advanced Magnet with Broadband Optics (RAMBO), a table-top pulsed magnet that combines strong magnetic fields with diverse spectroscopies 27 . A schematic of RAMBO is illustrated in Supplementary Fig. 1 and is discussed in Supplementary Note 1. ...
Exotic quantum vacuum phenomena are predicted in cavity quantum electrodynamics systems with ultrastrong light-matter interactions. Their ground states are predicted to be vacuum squeezed states with suppressed quantum fluctuations owing to antiresonant terms in the Hamiltonian. However, such predictions have not been realized because antiresonant interactions are typically negligible compared to resonant interactions in light-matter systems. Here we report an unusual, ultrastrongly coupled matter-matter system of magnons that is analytically described by a unique Hamiltonian in which the relative importance of resonant and antiresonant interactions can be easily tuned and the latter can be made vastly dominant. We found a regime where vacuum Bloch-Siegert shifts, the hallmark of antiresonant interactions, greatly exceed analogous frequency shifts from resonant interactions. Further, we theoretically explored the system’s ground state and calculated up to 5.9 dB of quantum fluctuation suppression. These observations demonstrate that magnonic systems provide an ideal platform for exploring exotic quantum vacuum phenomena predicted in ultrastrongly coupled light-matter systems. Ultrastrong light-matter interactions with dominant antiresonant terms are expected to give rise to interesting phenomena such as quantum fluctuation suppression. Here, the authors propose a system of ultrastrongly coupled magnon modes in a rare earth orthoferrite as a platform for exploring such phenomena.
... Thus, more sophisticated forms of sampling, also discussed in Section 2.2, must be implemented. Nonetheless, the allure of marrying magnetic fields exceeding 30 T with THz-TDS has motivated the development of several pulsed THz time-domain magnetospectroscopy facilities [29, 33,34,41,42,[73][74][75]. ...
... One facility that combines pulsed magnetic fields up to 30 T with THz-TDS was developed at Rice University, USA [74]. This magnet, known as the Rice Advanced Magnet with Broadband Optics (RAMBO), is a unique, table-top magnet that allows easy optical access to samples subjected to pulsed magnetic fields up to 30 T. The magnet measures only 17 cm in width with a bore diameter of 12 mm. ...
There are a variety of elementary and collective terahertz-frequency excitations in condensed matter whose magnetic field dependence contains significant insight into the states and dynamics of the electrons involved. Often, determining the frequency, temperature, and magnetic field dependence of the optical conductivity tensor, especially in high magnetic fields, can clarify the microscopic physics behind complex many-body behaviors of solids. While there are advanced terahertz spectroscopy techniques as well as high magnetic field generation techniques available, a combination of the two has only been realized relatively recently. Here, we review the current state of terahertz time-domain spectroscopy (THz-TDS) experiments in high magnetic fields. We start with an overview of time-domain terahertz detection schemes with a special focus on how they have been incorporated into optically accessible high-field magnets. Advantages and disadvantages of different types of magnets in performing THz-TDS experiments are also discussed. Finally, we highlight some of the new fascinating physical phenomena that have been revealed by THz-TDS in high magnetic fields.
... Thus, more sophisticated forms of sampling, also discussed in Section II B, must be implemented. Nonetheless, the allure of marrying magnetic fields exceeding 30 T with THz-TDS has motivated the development of several pulsed THz time-domain magnetospectroscopy facilities [29,33,34,40,41,[71][72][73]. ...
... One facility that combines pulsed magnetic fields up to 30 T with THz-TDS was developed at Rice University [72]. This magnet, known as the Rice Advanced Magnet with Broadband Optics (RAMBO), is a unique, table-top magnet that allows easy optical access to samples subjected to pulsed magnetic fields up to 30 T. The magnet measures only 17 cm in width with a bore diameter of 12 mm. ...
There are a variety of elementary and collective terahertz-frequency excitations in condensed matter whose magnetic field dependence contains significant insight into the states and dynamics of the electrons involved. Often, determining the frequency, temperature, and magnetic field dependence of the optical conductivity tensor, especially in high magnetic fields, can clarify the microscopic physics behind complex many-body behaviors of solids. While there are advanced terahertz spectroscopy techniques as well as high magnetic field generation techniques available, combination of the two has only been realized relatively recently. Here, we review the current state of terahertz time-domain spectroscopy experiments in high magnetic fields. We start with an overview of time-domain terahertz detection schemes with a special focus on how they have been incorporated into optically accessible high-field magnets. Advantages and disadvantages of different types of magnets in performing terahertz time-domain spectroscopy experiments are also discussed. Finally, we highlight some of the new fascinating physical phenomena that have been revealed by terahertz time-domain spectroscopy in high magnetic fields.
... The same limitation will apply to H-based superconductors as studies now focus on critical fields properties [8][9][10]. This limitation makes vortex pinning in superconductors at fields above 20 T almost uncharted territory [20][21][22][23][24]. So, a sensible pathway forward is to achieve J c measurements in pulsed magnetic fields [25][26][27], as peak fields up to 100 T are routinely achievable in the millisecond range at large facilities [28][29][30] and 30 T table-top systems are available [31]. ...
... We performed nonlinear I -V curves measurements in pulsed magnetic fields up to 50 T in YGBCO-based coated conductors, showing excellent reproducibility and agreement with measurements in the same samples performed under dc magnetic fields. This technique enables routine J c measurements up to 30 T in table-top pulsed-field systems [31] and opens up the exploration of superconductors' solid vortex phase up to 100 T, thus unlocking the access to a region of lower temperatures and higher fields where the influence of thermal fluctuations should diminish and quantum and field-induced disorder should compete. The smart I -V curve technique can also be applied to a large variety of condensed-matter systems [1,2,4]. ...
Nonlinear electrical transport studies at high pulsed magnetic fields, above the range accessible by dc magnets, are of direct fundamental relevance to the physics of superconductors, domain-wall, charge-density waves, and topological semimetal. All-superconducting very high field magnets also make it technologically relevant to study vortex matter in this regime. However, pulsed magnetic fields reaching 100 T in milliseconds impose technical and fundamental challenges that have prevented the realization of these studies. Here, we present a technique for sub-microsecond smart current-voltage measurements, which enables the determination of the superconducting critical current in pulsed magnetic fields, beyond the reach of any dc magnet. We demonstrate the excellent agreement of this technique with low dc field measurements on Y0.77Gd0.23Ba2Cu3O7 coated conductors with and without BaHfO3 nanoparticles. Exploring the uncharted high-magnetic-field region, we discover a characteristic influence of the magnetic field rate of change (dH/dt) on the current-voltage curves in a superconductor. We fully capture this unexplored vortex physics through a theoretical model based on the asymmetry of the vortex-velocity profile produced by the applied current.
... [8][9][10] This limitation makes vortex pinning in superconductors at fields above 20 T almost uncharted territory [20][21][22][23][24]. So, a sensible pathway forward is to achieve J c measurements in pulsed magnetic fields [25][26][27], as peak fields up to 100 T are routinely achievable in the millisecond range at large facilities [28][29][30] and 30 T table-top systems are available. [31] Several technical and fundamental obstacles need to be cleared first. The measurement of J c in a superconductor typically involves measuring an I-V curve i.e. applying an electric current while monitoring that the voltage across the sample does not exceeds a set threshold. ...
... We performed non linear I-V curves measurements in pulsed magnetic fields up to 50 T in YGBCO based coated conductors, showing excellent reproducibility and agreement with measurements in the same samples performed under DC magnetic fields. This technique enables routine J c measurements up to 30 T in table-top pulsed field systems [31] and opens up the exploration of superconductors solid vortex phase up to 100 T, thus unlocking the access to a region of lower temperatures/higher fields where thermal fluctuation influence should diminish and quantum and field-induced disorder should compete. The smart I-V curve technique can also be applied to a large variety of condensed matter systems. ...
arXiv:1903.04658 : Non-linear electrical transport studies at high-pulsed magnetic fields, above the range accessible by DC magnets, are of direct fundamental relevance to the physics of superconductors, domain-wall, charge-density waves, and topological semi-metal. All-superconducting very-high field magnets also make it technologically relevant to study vortex matter in this regime. However, pulsed magnetic fields reaching 100 T in milliseconds impose technical and fundamental challenges that have prevented the realization of these studies. Here, we present a technique for sub-microsecond, smart, current-voltage measurements, which enables determining the superconducting critical current in pulsed magnetic fields, beyond the reach of any DC magnet. We demonstrate the excellent agreement of this technique with low DC field measurements on Y$_{0.77}$Gd$_{0.23}$Ba$_2$Cu$_3$O$_7$ coated conductors with and without BaHfO$_3$ nanoparticles. Exploring the uncharted high magnetic field region, we discover a characteristic influence of the magnetic field rate of change ($dH/dt$) on the current-voltage curves in a superconductor. We fully capture this unexplored vortex physics through a theoretical model based on the asymmetry of the vortex velocity profile produced by the applied current.
