Hideaki Takano

Resistance and susceptibility anomalies in IrTe{sub 2} and CuIr{sub 2}Te{sub 4}

AbstractIrTe2has the CdI2structure and CuIr2Te4has a defect-NiAs structure at room temperature. Both compounds show basically metallic behavior. Magnetic and resistance anomalies, showing a hysteresis in temperature, have been found in IrTe2and CuIr2Te4. On heating, the resistivity ρ exhibits a hump-shaped maximum around 270 and 250 K for IrTe2and CuIr2Te4, respectively. The magnetic susceptibility χ reveals a step-like anomaly which gives evidence of a difference in the value of the Pauli paramagnetism between the high- and low temperature sides, corresponding to the anomalous behavior in ρ. These anomalies of ρ and χ in IrTe2originate from a gradual structure deformation with temperature, where the crystal symmetry changes from high temperature trigonal

Magnetic properties of concentrated melt-spun Fe–Y amorphous alloys

P\overline 3 m1

Muon spin relaxation studies in single crystals YRu2Si2 and Ce(Ru1−xRhx)2Si2

to low temperature monoclinic C2/m.

μSR study of the heavy-electron system Ce(Ru1−xRhx)2Si2

Abstract A normal thiospinel CuIr 2 S 4 exhibits a temperature-induced metal–insulator (M–I) transition around 226 K with crystal structure transformation. In order to study gradual variations of the M–I transition by gentle chemical modification with increasing the number of 5d electron, we have prepared the polycrystalline samples of Cu(Ir 1− x Pt x ) 2 S 4 and have investigated the electrical and magnetic properties of these samples. The features of the M–I transition in the electrical resistivity vary gradually with Pt concentration x . No structural transformation has been observed for x =0.25 and 0.30, where the abrupt jump disappears in the resistivity and the magnetic susceptibility around the transition temperature.

Mechanical milling of MgB2

Abstract Phase diagram on melt-spun Fe x Y 100− x amorphous alloys was investigated through measurements of d M /d H , zero-field-cooled and field-cooled magnetization and EXAFS. The present result shows reentrant spin glass for 42⩽ x ⩽58 and spin glass for x ⩽40, which is different from previous studies for sputtered and other melt-spun samples. The magnetic phase change at x =40 can be attributed to the change of Fe–Fe distance or some other structural changes.

Magnetic properties of amorphous Mn100−xCex alloys

Abstract Mechanical milling of ordered and disordered Fe 72 Pt 28 alloys was performed by vibrating milling. A martensitic transformation is induced in both alloys by milling, and the fundamental crystal structure re-transforms from bcc to fcc with heating up to 750 K. We can obtain fcc Fe 72 Pt 28 with different degrees of structural disorder by mechanical milling and subsequent heating of disordered Fe 72 Pt 28 . The Curie temperature of fcc Fe 72 Pt 28 with different degrees of structural disorder increases with increasing structural disorder.

La substitution effect to the heavy-fermion state in structure-disordered Ce-Ru alloys

We have performed zero-field μSR measurements on high-quality single-crystalline samples of YRu 2 Si 2 , CeRu 2 Si 2 and Ce(Ru 0.85 Rh 0.15 ) 2 Si 2 from 2 K to 300 K. We got information on the diffusion and stopping site of muons in the ThCr 2 Si 2 structure from measurements on the non-magnetic reference compound YRu 2 Si 2 . The development of magnetic correlation of the Ce 4f moment was observed below 100 K on CeRu 2 Si 2 . Furthermore, the property of the antiferromagnetic ordering state of Ce(Ru 0.85 Rh 0.15 ) 2 Si 2 is discussed

Appearance of two magnetic phases in doped Lu1−xAxFeO3 (A=Ca,Sr)

Abstract We have performed zero- and longitudinal-field μSR measurements on polycrystalline Ce(Ru 1− x Rh x ) 2 Si 2 for x = 0 and 0.15 from 4 to 300 K. The development of a magnetic correlation has been found to start as high as room temperature for both systems with a quasistatic character. Another static inhomogeneous field partly occurs at 5.5 K for x = 0.15, suggesting a complicated antiferromagnetic ordering.