Takuo Sakon

Anisotropy in a Heavy Fermion Superconductor: UPd2Al3

We report on the anisotropy of magnetization, electrical resistivity and upper critical magnetic fields ( H C2 ) of UPd 2 Al 3 . The magnetization curve in the antiferromagnetically ordered state shows large anisotropy, indicating that the sublattice moments lie in the basal hexagonal plane. The value of -( d H C2 / d T ) at T C is estimated to be about 36 (kOe/K) for the magnetic field parallel and perpendicular to the hexagonal c -axis, and the upper critical field seems to be rather isotropic.

Antiferromagnetic Resonance and Magnetic Structure of GdAs

Electron spin resonance measurements on single-crystal and powder of GdAs have been performed in the temperature range from 4.2 to 40 K and in the frequency range from 55 to 585 GHz to obtain micro...

Heavy-electron behavior in a low-carrier-concentration compound YbAs

Low-temperature specific heat of YbAs has been measured down to about 50 mK. In the antiferromagnetic ordered state ( T N ∼0.5 K), the nuclear contribution is observed below about 150 mK. By subtraction of this contribution from the measured specific heat, the linear coefficient of the electronic specific heat is estimated to be about 270 mJ/K 2 mole. This value is extraordinarily large because the carrier concentration in YbAs is of the order of 0.01 per formula unit. This large mass enhancement may be ascribed to a mutual 4 f -spin compensation mechanism instead of the usual Kondo spin fluctuation. We also show that the magnetic field effect on the specific heat is rather small.

Cyclotron Resonance of GdAs

Cyclotron resonance measurements on a single crystal of GdAs have been performed in the temperature range from 4.2 to 0.5 K to obtain the cyclotron effective mass of the carriers at the Fermi level...

Field-induced strain of shape memory alloy Fe-31.2%pd using a capacitance method in a pulsed magnetic field

A system for the simultaneous measurement of magnetization and magnetic strain, which is designed to be used in a pulsed magnetic field, has been developed. In this system, a capacitor on a sample is used and its capacitance changes with the displacement of a sample due to the strain on the sample in a magnetic field. The most significant feature of this system is that magnetization and strain can be measured simultaneously. It is useful to compare the magnetization and magnetic strain (magnetostriction) with each other. Using this system, we have studied the precise magnetization and magnetic field-induced strain (MFIS) of the martensite metallic compound Fe–31.2%Pd (at.%) at temperatures down to 80 K in martensite phase, which is much lower than the martensitic transformation temperature TM=230 K. Large MFIS has been measured under a pulsed magnetic field with the time constant 6 ms, which corresponds to 80 Hz in frequency. It means that the MFIS occurs even in short-pulse magnetic fields.

Cyclotron Resonance of LaSb

Cyclotron resonance measurements on a single crystal of LaSb have been performed in the temperature range from 1.7 to 40 K and at the frequency range from 50 to 110 GHz to obtain the cyclotron effe...

Anisotropic Magnetic Properties and Anomalous Thermal Conductivity in the bc Plane of the Quasi-Two-Dimensional Spin System Cu3B2O6: Relation between the Thermal Conductivity and the Spin State in Magnetic Fields

We have measured the magnetic susceptibility in a magnetic field of 1 T (rotating the field direction) in the b c plane, the magnetization curve in magnetic fields up to 30 T and the thermal conduc...

Magnetic-Field-Induced Strain of Shape-Memory Alloy Fe3Pt Studied by a Capacitance Method in a Pulsed Magnetic Field

The precise magnetic-field-induced strain (MFIS) and magnetization of the martensite metallic compound Fe3Pt in a martensitic phase were studied in a pulsed magnetic field using the capacitance method at low temperatures down to 4.2 K, which is much lower than the martensitic transformation temperature TM=85 K. After zero field cooling, a pulsed magnetic field with a maximum frequency of 160 Hz was applied parallel to the [001]p axis. A large MFIS was measured. The value of the MFIS is ΔL/L=-1.7%. When the magnetic field was decreased, the recovery of the strain was observed. In the second applied field, a strain of about 0.6% was observed. This means that MFIS occurs even in short-pulse magnetic fields. MFIS was observed below 70 K. The largest strain was observed at 20 K. These results are almost the same as the MFIS in a steady magnetic field using a superconducting magnet.

Nonmagnetic Impurity Effects on S=1/2 Heisenberg Ladder Cu2(C5H12N2)2Cl4.

Magnetic measurements have been performed to investigate nonmagnetic impurity effects on a Zn-doped ladder system (Cu 1- x Zn x ) 2 (C 5 H 12 N 2 ) 2 Cl 4 . The paramagnetic contribution in the sus...

Magnetic Properties of Unusual Metal System TmS in High Magnetic Fields

Magnetic properties of TmS have been examined in high magnetic fields by means of resistivity, specific heat and magnetization measurements using a high quality single crystal. The high-field magnetization measurements indicate that the magnetization for H ∥ is quite suppressed at high fields. The observed results can be explained reasonably by taking into consideration of O 2 0 -type ferro electric quadrupolar (FQ) interactions and the crystalline electric field effect. The new phase which has been induced by applying magnetic fields, might be ascribed to the O 2 0 -type FQ ordering. The established magnetic field-temperature phase diagram implies that the antiferromagnetic interaction and O 2 0 -type FQ interaction coexist at low temperatures.