Observation of MnP magnetic clusters in room-temperature ferromagnetic semiconductor Zn1-xMnxGeP2 using nuclear magnetic resonance

Abstract

We investigated chalcopyrite Zn1-xMnxGeP2 polycrystals, which have been reported as a room-temperature ferromagnetic semiconductor, with Mn concentrations of x=0.08 and 0.15 using Mn-55 and P-31 nuclear magnetic resonance spectroscopy. The samples were made by the same process and showed the same crystallographic and magnetic behavior as in the previous report, but the experimental results indicated that more than 90% of Mn atoms were in a MnP impurity phase and the MnP cluster size was tens of nanometers. No evidence of Mn atom substitution in the host ZnGeP2 lattice was observed and the magnetic property of Zn1-xMnxGeP2 was determined to be that of the MnP magnetic clusters, at least in the bulk. The inconsistency of the conclusions with x-ray diffraction data is a result of the weak crystallinity of MnP phase. (C) 2003 American Institute of Physics.