A high-resolution electron microscopy study of the structure of the (1/0,2/1) and (1/1,1/1) decagonal approximants in Ga6Mn5

Abstract

Structural models of the two closely related orthorhombic approximants in the Ga6Mn5 alloy, the (1/0,2/1) approximant with a = 0.77 nm, b = 1.25 nm and, c = 2.36 nm and the (1/1,1/1) approximant with a = 1.26 (0.77 where T = (1 + 5 1/2)/2)nm, b = 1.25 nm and c = 1.48 2.36/ nm, have been deduced from their high-resolution electron microscopy (HREM) images and from the known structures of the orthorhombic Al60Mn11Ni4(1/0,2/1) and Al3Mn (1/1,1/1) approximants. Experimental and simulated electron diffraction patterns and (010) HREM images are compared. Some typical domain and fault structures in these two approximants in the (010) HREM images are discussed.