The microstructure and magnetic properties of Mg–Cu substituted W-type barium hexaferrites

Abstract

The W-type barium hexagonal ferrites BaMg_2−xCu_xFe₁₆O₂₇, 0 ≤ x ≤ 1.4, were prepared by the ceramics process at 1270°C for 3 h, respectively. The X-ray diffraction (XRD) results revealed that the ferrites were single W-phase as Cu content (x) ≤0.6, while the second phase (α-Fe₂O₃) began to occur when Cu content (x) ≥0.8. Permanent magnetic properties of the magnets were measured by a B–H hysteresis curve measurements. The effects of the Cu content (x) on the permenant magnetic properties of the magnets were studied systematically. As a result, the remanence (B_r) first increased with the increase of Cu content (x) and reached the maximum value of 402.4 mT at x = 0.6, then decreased when x continued to increase. Morever, the intrinsic coercivity (H_cj), magnetic induction coercivity (H_cb) and maximum energy product [(BH)_max] decreased obviously with the x increased.