MOSSBAUER STUDY ON A DILUTED TRIANGULAR ANTIFERROMAGNET LUFEMGO4

Mossbauer study of Fe-57 of a single crystal LuFeMgO4, a diluted trian gular antiferromagnet, reveals two kinds of spin behavior, a weakly fr ustrated and a strongly frustrated ones. One kind of spin aligns along the c-axis with antiferromagnetic correlation and contributes to an a lmost constant H-hf at temperatures below T-cusp (spin glass like tran sition temperature), while the other behaves like a Heisenberg spin in a triangular antiferromagnet rapidly fluctuating with 120 degrees str ucture, and contributes to a slightly smaller and temperature dependen t H-hf This behavior is explained in relation to the magnetic properti es.