Direct Observation of the High Magnetic Field Effect on the Jahn-Teller State in TbVO 4

Capatina

et al. 2012

We present a pulsed-magnet system that enables x-raysingle-crystaldiffraction in addition to powder and spectroscopic studies with the magnetic field applied on or close to the scattering plane. The apparatus consists of a single large-bore solenoid, cooled by liquid nitrogen. A second independent closed-cycle cryostat is used for cooling samples near liquid helium temperatures. Pulsed magnetic fields close to ∼30 T with a zeroto-peak-field rise time of ∼2.9 ms are generated by discharging a 40 kJ capacitor bank into the magnet coil. The unique characteristic of this instrument is the preservation of maximum scattering angle (∼23.6°) on the entrance and exit sides of the magnet bore by virtue of a novel double-funnel insert. This instrument will facilitate x-ray diffraction and spectroscopic studies that are impractical, if not impossible, to perform using split-pair and narrow-opening solenoid magnets. Furthermore, it offers a practical solution for preserving optical access in future higher-field pulsed magnets. KeywordsPhysics, Magnets, Magnetic fields, Sapphire, X-ray diffraction, Copper Disciplines Condensed Matter Physics CommentsThe following article appeared in Review of Scientific Instruments 83 (2012) We present a pulsed-magnet system that enables x-ray single-crystal diffraction in addition to powder and spectroscopic studies with the magnetic field applied on or close to the scattering plane. The apparatus consists of a single large-bore solenoid, cooled by liquid nitrogen. A second independent closedcycle cryostat is used for cooling samples near liquid helium temperatures. Pulsed magnetic fields close to ∼30 T with a zero-to-peak-field rise time of ∼2.9 ms are generated by discharging a 40 kJ capacitor bank into the magnet coil. The unique characteristic of this instrument is the preservation of maximum scattering angle (∼23.6 • ) on the entrance and exit sides of the magnet bore by virtue of a novel double-funnel insert. This instrument will facilitate x-ray diffraction and spectroscopic studies that are impractical, if not impossible, to perform using split-pair and narrow-opening solenoid magnets. Furthermore, it offers a practical solution for preserving optical access in future higher-field pulsed magnets.

Section: Jahn-teller Effects In Tbvomentioning

confidence: 75%

Section: Jahn-teller Effects In Tbvomentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A single-solenoid pulsed-magnet system for single-crystal scattering studies

Capatina

et al. 2012

“…With the advent of modern synchrotron x-ray sources, significant efforts have also been invested to study field-induced phenomena with x-rays. [6][7][8][9][10][11][12][13] While these efforts have led to many applications of x-ray spectroscopic and imaging techniques to study field effects in materials, [6][7][8] progress in x-ray scattering studies of single-crystal samples in magnetic fields with split-pair and solenoid magnets have been relatively slower due to two long-standing obstacles. First, optical access required for scattering studies is restricted due to magnet geometries.…”

Section: Introductionmentioning

confidence: 99%

A novel approach for x-ray scattering experiments in magnetic fields utilizing trapped flux in type-II superconductors

Das

et al. 2012

Self Cite

We introduce a novel approach to x-ray scattering studies in applied magnetic fields by exploiting vortices in superconductors. This method is based on trapping magnetic flux in a small disk-shaped superconductor (known as a trapped field magnet, TFM) with a single-crystal sample mounted on or at close proximity to its surface. This opens an unrestricted optical access to the sample and allows magnetic fields to be applied precisely along the x-ray momentum transfer, facilitating polarization-sensitive experiments that have been impractical or impossible to perform to date. The TFMs used in our study remain stable and provide practically uniform magnetic fields for days, which are sufficient for comprehensive x-ray diffraction experiments, specifically x-ray resonance exchange scattering (XRES) to study field-induced phenomena at a modern synchrotron source. The TFM instrument has been used in a "proof-of-principle" XRES study of a meta-magnetic phase in a rare-earth compound, TbNi 2 Ge 2 , in order to demonstrate its potential. KeywordsPhysics and Astronomy, Magnetic fields, X-ray scattering, Magnets, X-ray optics, Superconductors We introduce a novel approach to x-ray scattering studies in applied magnetic fields by exploiting vortices in superconductors. This method is based on trapping magnetic flux in a small disk-shaped superconductor (known as a trapped field magnet, TFM) with a single-crystal sample mounted on or at close proximity to its surface. This opens an unrestricted optical access to the sample and allows magnetic fields to be applied precisely along the x-ray momentum transfer, facilitating polarizationsensitive experiments that have been impractical or impossible to perform to date. The TFMs used in our study remain stable and provide practically uniform magnetic fields for days, which are sufficient for comprehensive x-ray diffraction experiments, specifically x-ray resonance exchange scattering (XRES) to study field-induced phenomena at a modern synchrotron source. The TFM instrument has been used in a "proof-of-principle" XRES study of a meta-magnetic phase in a rare-earth compound, TbNi 2 Ge 2 , in order to demonstrate its potential. Disciplines Condensed Matter Physics

“…For measurements requiring maximum fields, as much as ∼20 minutes of waiting in between successive shots may be required for the magnet to cool down to operating temperature, and therefore it is critical to extract as much information as possible from each pulse. Due to high brightness of the third-generation synchrotron sources, these pulsed magnets have been successfully used in numerous studies [3,4,[13][14][15][16][17][18][19][20][21]; nevertheless, increases in measurement efficiency are highly desirable. In this article we describe a novel use of a fast one-dimensional µ-strip detector for diffraction measurements.…”

mentioning

confidence: 99%

Time-resolved one-dimensional detection of x-ray scattering in pulsed magnetic fields

Ross

et al. 2012

We have developed an application of a one-dimensional micro-strip detector for capturing x-ray diffraction data in pulsed magnetic fields. This detector consists of a large array of 50 µm-wide Si strips with a full-frame read out at 20 kHz. Its use substantially improves data-collection efficiency and quality as compared to point detectors, because diffraction signals are recorded along an arc in reciprocal space in a time-resolved manner. By synchronizing with pulsed fields, the entire field dependence of a two-dimensional swath of reciprocal space may be determined using a small number of field pulses.