ELECTRON-PARAMAGNETIC-RESONANCE OF EU2-XEUXSE (X=0.013) WITH A CUBIC STRUCTURE( THE DILUTE MAGNETIC SEMICONDUCTOR PB1)

Detailed X-band (about 9.5 GHz) electron paramagnetic resonance (EPR) measurements were carried out at 295, 77 and 4.2 K on the Eu2+ ion in a Pb1-xEuxSe single crystal. The values of the spin-Hamiltonian parame ters have been determined by a simultaneous fitting of all the EPR lin e positions recorded for various orientations of the external magnetic field in the [010] plane using a rigorous least-squares fitting proce dure. The absolute sign of the zero-field splitting parameter b(4) was determined to be positive from the relative intensities of lines at l iquid-helium temperature (4.2 K). The excellent fit of the line positi ons to a cubic spin Hamiltonian confirms that the site symmetry for Eu 2+ ions is, indeed, cubic in the Pb1-xEuxSe single crystal over the te mperature range 4.2-295 K. The Dynosian shape of the EPR lines indicat es the metallic nature of the Pb1-xEuxSe sample. The nearest-neighbour Eu2+-Eu2+ exchange interaction has been estimated to be 20.4 GHz (ant iferromagnetic) from the exchange-pair EPR spectrum at 4.2 K. The hype rfine interaction constants for the isotopes Eu-151 and Eu-153 have be en estimated.