Development of high-pressure, high-field and multifrequency electron spin resonance system

Abstract

The electron spin resonance (ESR) system which covers the magnetic field region up to 16 T, the quasicontinuous frequency region from 60 to 700 GHz, the temperature region from 1.8 to 4.2 K, and the hydrostatic pressure region up to 1.1 GPa has been developed. This is the first pulsed high-field and multifrequency ESR system with the pressure region over 1 GPa as far as we know. Transmission ESR spectra under hydrostatic pressure can be obtained by combining a piston-cylinder-type pressure cell and the pulsed magnetic field ESR apparatus. The pressure cell consists of a NiCrAl cylinder and sapphire or zirconia inner parts. The use of sapphire or zirconia as inner parts enables us to observe ESR under pressure because these inner parts have high transmittance for the electromagnetic wave with millimeter and submillimeter wavelengths. We have successfully applied this system for the pressure dependence measurements of an isolated spin system NiSnCl(6)6H(2)O up to 1.1 GPa. It was found that the single ion anisotropy parameter D of this compound strongly depends on pressure. The parameter D is approximately proportional to the pressure up to 0.75 GPa, and the relation between D and the pressure can be used for the pressure calibration of this high-field and high-pressure ESR system.

Development of High-Field ESR System Using SQUID Magnetometer and its Application to Measurement under High Pressure

“…6. We already found that the D-value increases as the pressure is increased for this material [24]. The dotted and solid lines in Fig.…”

“…The cylinder and clamping bolts are all made of non-magnetic CuBe alloy. In order to introduce the electromagnetic wave into the sample space, the upper inner parts made of CuBe alloy were replaced by those made of ZrO 2 which was already known to have relatively good transmittance of electromagnetic wave [24] as shown in Fig. 4.…”

Tools for magnetostructural correlations for the 3d8(3A2 state) ions at orthorhombic sites: Comparative study with applications to Ni2+ ions in Y2BaNiO5 and Nd2BaNiO5

“…Applications for Ni 2 þ (S ¼1) ions in the Haldane gap systems Y 2 BaNiO 5 and Nd 2 BaNiO 5 have been worked out to illustrate the usefulness of these tools. The proposed tools may also enable better understanding of the spectroscopic properties of Ni 2 þ ions in other crystals as well as facilitate applications of high pressure and/or HMF-EMR measurements [63] in the studies of Haldane gap systems, which are still scarce [64].…”

Continuous-wave far-infrared ESR spectrometer for high-pressure measurements

“…To date, a combination of high-field/high-frequency ESR system with a high hydrostatic pressure vessel operating above 1 GPa has been reported by only one group [20]. It is a pulsed high-field, multi-frequency (60-700 GHz) system, that operates up to 17 T and covers the hydrostatic pressure range up to 1.1 GPa.…”

“…It features a non-resonant transmission-type pressure vessel, which is equipped with two microwave-transparent sapphire plugs. This pressure vessel is located in the same cryostat compartment as the InSb microwave detector, which limits the operating temperature range to 1.8-4.2 K. Notwithstanding the above technical limitation, the non-resonant high-frequency approach described in [20] offers a remarkable simplification of the overall system design, because the complicated resonant microwave structures can be avoided without sacrificing the spectrometer performance [2,21].…”