High-field ESR measurements of quantum spin system under high pressure

Frequency Extension to the THz Range in the High Pressure ESR System and Its Application to the Shastry–Sutherland Model Compound SrCu2(BO3)2

“…And it does not reach 1 GPa even if several parts are replaced by that made of the tougher ZrO 2 -based ceramic. [5][6][7][8][9][10][11][12][13][14][15] On the other hand, the ZrO 2 -based ceramic has very high toughness and it is much cheaper than sap-phire. However, the ZrO 2 -based ceramic does not have enough transmission especially for the higher frequency region.…”

“…Náfrádi et al whose system is a similar type with us started their development later than us and they have the system with the maximum field up to 16 T, the pressure region up to 1.6 GPa and the frequency region from 105 to 420 GHz. 2 On the other hand, in our systems the frequency can be varied very widely, which includs the socalled THz region defined as the frequency region from 0.1 to 10 THz, 4 since we simply combine the piston-cylinder pressure cells with the transmission-type high-field ESR system using the pulsed high magnetic field [5][6][7][8][9][10][11][12][13][14][15][16][17][18] or the static magnetic field. 1,[19][20][21][22] The most characteristic point of our pressure cell is that all inner parts are made of sapphire and ZrO 2 -based ceramic.…”

“…Therefore, our high-pressure ESR systems have proved to be one of the most powerful means to study quantum spin systems. 1,[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] So far, we developed the pressure cell with the moderate pres- Phase diagram for the Shastry-Sutherland model. 26 sure range below 1 GPa and the wide frequency region from 70 to 700 GHz, [5][6][7][8][9][10][11][12][13][14][15] and that with the higher pressure range up to 1.5 GPa and the limited frequency region from 70 to 400 GHz.…”

“…1,[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] So far, we developed the pressure cell with the moderate pres- Phase diagram for the Shastry-Sutherland model. 26 sure range below 1 GPa and the wide frequency region from 70 to 700 GHz, [5][6][7][8][9][10][11][12][13][14][15] and that with the higher pressure range up to 1.5 GPa and the limited frequency region from 70 to 400 GHz. 1,[16][17][18][19][20] Recently, we also developed a hybrid-type pressure cell with larger sample space and higher pressure region for large bore magnet, which covers the frequency region form 50 to 400 GHz and the pressure up to 2.5 GPa.…”

“…On the other hand, in our systems, the frequency can be varied very widely, which includes the so-called THz region defined as the frequency region from 0.1 to 10 THz, since we simply combine the piston–cylinder pressure cells with the transmission-type high-field ESR system using the pulsed high magnetic field − or the static magnetic field. ,− The most characteristic point of our pressure cell is that all inner parts are made of sapphire and ZrO 2 -based ceramic. They have both the toughness and the transmission in the THz region, and this enables us to observe the transmitted light through the pressure cell in the wide frequency region.…”