Giant Anisotropy of the ESR Linewidths of Mn²⁺ Centers in Pb_{1 – x}Mn_xS and Pb_{1 – x – y}Cu_yMn_xS (x = 0.002, y = 0.002) Narrow-Gap Semiconductors

Abstract

Giant anisotropy of the X-band electron spin resonance linewidths at the electronic transitions (|±5/$\left. 2 \right\rangle$ $\leftrightarrow$ |±3/$\left. 2 \right\rangle$) and (|±3/$\left. 2 \right\rangle$ $\leftrightarrow$ |±1/$\left. 2 \right\rangle$) of the Mn²⁺ centers (⁶S, S = 5/2, I = 5/2) is detected in a Pb_1−xMn_xS narrow-gap semiconductor crystal in the temperature range of 5–150 K. Somewhat weaker ESR linewidth anisotropy at transitions (|±5/$\left. 2 \right\rangle$ $\leftrightarrow$ |±3/$\left. 2 \right\rangle$) and (|±3/$\left. 2 \right\rangle$ $\leftrightarrow$ |±1/$\left. 2 \right\rangle$) is observed for the Pb_{1 − x − y}Cu_yMn_xS (x = 0.002; y = 0.002) semiconductor crystal in the same range of temperatures. The temperature dependences of the widths and amplitudes of the observed ESR lines are described, and the nature of the linewidth anisotropy is discussed.