ASYMMETRY AND DISTORATION OF THE ELECTRON PARAMAGNETIC RESONANCE PROFILE IN TMMC: Cu AT GENERAL TEMPERATURE

Abstract

In this paper an experimental study of the asymmetry in the electron paramagnetic resonance ( EPR ) line shape in one dimension magnetic system has been presented. The system studied is Tetra methylamonium Manganese trichloride (TMMC), and TMMC doped with different concentrations of Cu ions. Several parameters regarding the asymmetry jf the EPR line shape about the resonance position have been measured. These are the ratios of the I+ /I- , I+ /I- , ΔH+ / ΔH- and ΔH’+/ ΔH'- where I and I' are the amplitudes of the maxima of the first and second derivatives of EPR absorption line. AH is the livewidth with respect to the resonance position and where dX/dH has extremum. AH’ is the width with respect to the resonance position and where d2X/dH2 has extremum. The + and - signs show the high and low field sides with respect to Hc that is H >HC and H <HC. For symmetric line shape these ratios are egual to unity but our experiments shows that these are different than unity. It is also shown that this asymmetry is strongly 0 dependent, where 0 is the angle the erystal C-axis makes with the static-field, and also enhanced by the impurity. These experiments were performed at two different temperatures T=296°k and T-112°k. It is seen that at low temperature the line is more symmetric