H. Tsujii

High magnetic field phase diagram of PrOs4Sb12

The magnetic phase diagram of PrOs4Sb12 has been investigated by specific heat measurements between 8 and 32 T. A new Schottky anomaly, due to excitations between two lowest crystalline-electric-field (CEF) singlets, has been found for both H parallel (100) and H parallel (110) above the field where the field-induced ordered phase (FIOP) is suppressed. The constructed H-T phase diagram shows weak magnetic anisotropy and implies a crossing of the two CEF levels at about 8-9 T for both field directions. These results provide an unambiguous evidence for the Gamma(1) singlet being the CEF ground state and suggest the level crossing (involving lowest CEF levels) as the driving mechanism of FIOP.

High-field phase diagram of the Haldane-gap antiferromagnet Ni(C5H14N2)2N3(PF6)

We have determined the magnetic phase diagram of the quasi-one-dimensional

Specific heat of the S = 1 spin-dimer antiferromagnet Ba 3 Mn 2 O 8 in high magnetic fields

S=

Tomonaga-Luttinger Liquid in a Quasi-One-Dimensional S 1 Antiferromagnet Observed by Specific Heat Measurements

1 Heisenberg antiferromagnet

Thermodynamics of the up-up-down phase of the S=1/2 triangular-lattice antiferromagnet Cs2CuBr4

Ni (C_5 H_{14} N_2)_2 N_3 (PF_6)

Distributed τ2 effect in relaxation calorimetry

by specific heat measurements to 150 mK in temperature and 32 T in magnetic field. When field is applied along the spin-chain direction, a new phase appears at

Specific Heat of the S ¼ 1=2 Two-Dimensional Shastry-Sutherland Antiferromagnet SrCu2(BO3)2 in High Magnetic Fields

H_{c2}\approx 14

Calorimeter for a top-loading dilution refrigerator in high magnetic fields

T. For the previously known phases of field-induced order, accurate determination is made of the power-law exponents of the ordering temperature near the zero-temperature critical field

Specific heat of S=1 quasi-1D antiferromagnet NDMAP in magnetic fields

H_c

FIELD-INDUCED TOMONAGA–LUTTINGER LIQUID OF A QUASI-ONE-DIMENSIONAL S = 1 ANTIFERROMAGNET

, owing to the four-fold improvement of the minimum temperature over the previous work. The results are compared with the predictions based on the Bose-Einstein condensation of triplet excitations. Substituting deuterium for hydrogen is found to slightly reduce the interchain exchange.