G. Kido

Magnetic phase transition between ferromagnetic and antiferromagnetic states in Ce(Fe1−xAlx)2

Abstract The cubic Laves phase compound Ce(Fe 0.95 Al 0.05 ) 2 exhibits a first order magnetic phase transition from antiferromagnetic to ferromagnetic state at ≈ 100 K with increasing temperature. This note gives the results of the Mossbauer effect of 57 Fe and the magnetic phase diagram in the external field vs. temperature plane.

Magnetostriction and magnetization processes in Hf1−xTaxFe2 under pulsed high magnetic fields

Abstract Transverse and longitudinal magnetostriction and magnetization processes were measured for a Laves phase compound of Hf 1- x Ta x Fe 2 polycrystal using pulsed high magnetic fields up to 440 kOe. Magnetic phase boundaries were determined for x =0.25 and 0.3. An isotropic forced magnetostriction was observed through the antiferromagnetic to ferromagnetic phase transition.

High-field susceptibility of pseudobinary compounds Gd(Co1−xNix)2

Abstract Measurements of magnetization were performed for the pseudobinary compounds Gd(Co1−xNix)2 (x = 0, 0.1,... , 0.9, 1.0) under magnetic fields up to 140 kOe at 4.2K. The concentration variation of the moment of the transition metal atoms and the high-field susceptibility were obtained. Both the magnetic moment of the transition metal atom and the high-field susceptibility were found to decrease monotonically with the concentration. The results are discussed in terms of the model of the exchange-enhanced paramagnetism.

Optical Investigation of Soliton in the One-Dimensional Ising-Like Antiferromagnet CsCoCl3

The dependence of the absorption spectra of CsCoCl 3 on temperature and a magnetic field was investigated. It was found that the energy difference between the exciton line and its hot sideband is nearly equal to the soliton energy, and the intensity of the hot band is proportional to the thermal probability of the soliton below T N1 . Therefore, it was concluded that the hot band is ascribed to the exciton creation at the thermally excited soliton.

Forced magnetostrictions on MnAs1−xPx (x<0.275) under pulsed magnetic field up to 300 kOe

Abstract The magnetostrictions are measured in MnAs 1− x P x compounds by a capacitance method using pulsed high magnetic field up to 300 kOe. Discontinuous volume expansion was induced by the external field accompanying a structural phase transition from the MaP-type to the NiAs-type and a magnetic phase transition from paramagnetism to ferromagnetism.

Shubnikov-de Haas effect in CaVO3−y

Abstract We have observed magnetoresistance oscillations in CaVO 3−y single crystals below 4.2 K and in fields above 10 Tesla. The oscillation frequency is about 300 Tesla. This frequency corresponds to a surface cross section of 3×10 14 cm -2 in the reciprocal lattice space for cubic CaVO 3 . This is 1% of the cross section of the first Brillouin zone.

Optical investigations of YbCrO3 under high magnetic fields. I: Yb3+ absorption spectra

Optical absorption spectra corresponding to the 2 F 7/2 → 2 F 5/2 transition of Yb 3+ in YbCrO 3 were investigated under high magnetic fields. The energy positions of these spectra remarkably changed at the metamagnetic transition where the weak ferromagnetic moment of the Cr 3+ spins reverses its direction. From the analysis of the spectral change at the transition, the microscopic mechanism of the metamagnetic transition were elucidated. In the energy region of the 2 F 7/2 → 2 F 5/2 transition of Yb 3+ , besides single-ion excitations, cooperative absorption spectra corresponding to the Yb 3+ exciton coupled with Cr 3+ magnon and the Yb 3+ exciton coupled with Yb 3+ spin-flip were observed. From the analysis of these cooperative absorption spectra, the behavior of the Cr 3+ magnon mode and the Yb 3+ spin-flip mode under high magnetic fields was investigated.

Optical Investigations of YbCrO3 under High Magnetic Fields. II. Cr3+–Yb3+ Two-Exciton Absorption

In YbCrO 3 , we have observed Cr 3+ –Yb 3+ two-exciton absorption spectra ( A - E bands) corresponding to the 4 A 2 → 2 E , 2 T 1 transition of Cr 3+ and the 2 F 7/2 → 2 F 5/2 transition of Yb 3+ . Under high magnetic fields, we have found that a bound state appears on the lowest energy side of the A band and has a strong dependence on external magnetic fields.