MAGNETOMETRIC AND MOSSBAUER STUDIES ON MAGNETIC-PROPERTIES OF PSEUDO-TERNARY COMPOUNDS Y(CO1-XFEX)(4)B(0-LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-0.35)

Magnetization measurements as well as Mossbauer spectroscopy have been performed on pseudo-ternary Y(Co1_xFex)(4)B (0 less than or equal to x less than or equal to 0.35) compounds in order to investigate their magnetic properties. Powder samples aligned in a magnetic field at room temperature were used for the magnetization and X-ray diffraction measurements. The spin-reorientation transition, which was a change in the magnetization direction from parallel to the c.axis below a transition temperature T-sr to one perpendicular to the c-axis above T-sr, was observed in very narrow Fe concentration range 0 less than or equal to x <less than or equal to >0.03. All the compounds above x = 0.05 have a magnetization direction in the c-plane over the whole temperature range below Tc. The magnetic x-T phase diagram is determined by these results. The Mossbauer spectra measured for 0.05 less than or equal to x less than or equal to 0.35 reveal a strong preferential occupation of Fe for the 2c site. The average Fe moment is nearly constant by 1.04 mu(B) below x = 0.1 and increase above x = 0.1 up to 1.17 mu(B) at x = 0.35. Averaged Co moment increases monotonously from 0.69 mu(B) at X = 0 to 1.15 mu(B) at x = 0.35.