Bingzhi Jiang

Temperature dependence of soft magnetic properties in amorphous Co69Fe4.5Cu1.5Si10B15 alloy

The temperature dependence of soft magnetic properties in amorphous Co69Fe4.5Cu1.5Si10B15 alloy was investigated by the changes of incremental permeability ratio (PR) and magnetoimpedance ratio (MIR) as a function of temperature from 10 to 300 K. The temperature dependence of PR and MIR is directly related to the temperature dependence of soft magnetic properties. The soft magnetic properties in Co69Fe4.5Cu1.5Si10B15 alloy annealed at 400 °C are very stable for temperature variation at low temperature. The spin wave stiffness constant, D, was estimated from the temperature dependence of the magnetization at low temperature.

Local structure and magnetic properties of mechanical alloyed Co–C compositions

Formation of nanocrystalline Co particles embedded in an amorphous C matrix produced by the mechanical alloying process was studied. The formation of the Co5C95 alloy was examined by the x-ray diffraction (XRD) and extended x-ray absorption fine structure methods. XRD analysis displayed the decrease in the Co grains size, the transformation from the face-center-cubic (fcc)+hexagonal close-packed (hcp) phases to the hcp phase and an amorphization of carbon matrix with milling time. At the early stage of milling, the coercivity, HC, increased because of the higher hcp phase HC than that of the fcc phase. Partial HC increase could be also caused by the decrease of Co particles size. The subsequent powder milling led to the decrease in the HC due to thermal process and/or due to the transformation of hcp-Co to a random close-packed phase under a long-term milling. Magnetization of the compositions decreased gradually with milling. The size of single domain particles after the 60 h of milling was about 10 nm. ...

Magnetic anomalies of YIG films obtained by crystallization of structural complexes

Abstract Yttrium–iron garnet films were grown by liquid phase epitaxy from a weakly dissociated solution-melt using structural complexes. Anomalies in the temperature dependence of the magnetization are revealed at temperatures lower as well as higher than the Neel temperature. For the first time, a change of curvature is observed in the temperature dependence of the magnetization under applied magnetic field.

Local structures of nanostructured (FexCo1-x)75C25(FexCo1-x)75C25 alloys

The structural and magnetic properties of mechanically alloyed (FexCo1-x)75C25(FexCo1-x)75C25 (x=0x=0, 0.2, 0.5, 0.8, 1) alloys were studied as a function of Fe content. The local structural change of FeCo–C has been investigated by means of XRD, EXAFS and Mossbauer spectrometry. XRD pattern from 25h alloyed FeCo–C powders indicated cohenite like phases. EXAFS analysis showed (FeCo)3C(FeCo)3C phase formation in x=0.2x=0.2, 0.5 and 0.8, respectively. Mossbauer analysis reveals that Fe(Co)33C phase as dominant phase decreased with the Fe content decrease, in a good agreement with EXAFS analysis.

Local structures of nanostructured (FexCo1-x)75C25 alloys

The structural and magnetic properties of mechanically alloyed (FexCo1-x)75C25(FexCo1-x)75C25 (x=0x=0, 0.2, 0.5, 0.8, 1) alloys were studied as a function of Fe content. The local structural change of FeCo–C has been investigated by means of XRD, EXAFS and Mossbauer spectrometry. XRD pattern from 25h alloyed FeCo–C powders indicated cohenite like phases. EXAFS analysis showed (FeCo)3C(FeCo)3C phase formation in x=0.2x=0.2, 0.5 and 0.8, respectively. Mossbauer analysis reveals that Fe(Co)33C phase as dominant phase decreased with the Fe content decrease, in a good agreement with EXAFS analysis.

Local structures of nanostructured alloys

The structural and magnetic properties of mechanically alloyed (FexCo1-x)75C25(FexCo1-x)75C25 (x=0x=0, 0.2, 0.5, 0.8, 1) alloys were studied as a function of Fe content. The local structural change of FeCo–C has been investigated by means of XRD, EXAFS and Mossbauer spectrometry. XRD pattern from 25h alloyed FeCo–C powders indicated cohenite like phases. EXAFS analysis showed (FeCo)3C(FeCo)3C phase formation in x=0.2x=0.2, 0.5 and 0.8, respectively. Mossbauer analysis reveals that Fe(Co)33C phase as dominant phase decreased with the Fe content decrease, in a good agreement with EXAFS analysis.