Magnetic domain observations in Fe-Ga alloys

TY - JOUR

T1 - Magnetic domain observations in Fe-Ga alloys

AU - Mudivarthi..[et al.], C.

AU - Na, S. M.

AU - Schaefor, R.

AU - Laver, Mark

PY - 2010/7/1

Y1 - 2010/7/1

N2 - The domain structure of Fe-Ga bulk alloys is investigated with magnetic force (MFM) and magneto-optic Kerr microscopy. Published domain observations on this class of materials predominantly reveal maze-like domain patterns that indicate out-of-plane magnetization, i.e. out-of-plane anisotropy. Contrary to the belief that this anisotropy is due to the presence of nanoscale heterogeneities [1,2] (Bai et al., 2005, 2009), we show that it is due to a damaged surface layer caused by standard mechanical polishing. The surface conditions in Fe-Ga alloys are more sensitive to stress-induced damage than in pure α-Fe. This is explained as being due to increased magnetostriction. We demonstrate that the damaged surface layer can be removed with an additional polishing step using colloidal amorphous silica. On (0 0 1) bulk crystal surfaces, the domain structures, obtained after the removal of the damaged surface layer, reveal in-plane magnetization with sharp and straight 90° and 180° domain walls that are expected in these alloys.

AB - The domain structure of Fe-Ga bulk alloys is investigated with magnetic force (MFM) and magneto-optic Kerr microscopy. Published domain observations on this class of materials predominantly reveal maze-like domain patterns that indicate out-of-plane magnetization, i.e. out-of-plane anisotropy. Contrary to the belief that this anisotropy is due to the presence of nanoscale heterogeneities [1,2] (Bai et al., 2005, 2009), we show that it is due to a damaged surface layer caused by standard mechanical polishing. The surface conditions in Fe-Ga alloys are more sensitive to stress-induced damage than in pure α-Fe. This is explained as being due to increased magnetostriction. We demonstrate that the damaged surface layer can be removed with an additional polishing step using colloidal amorphous silica. On (0 0 1) bulk crystal surfaces, the domain structures, obtained after the removal of the damaged surface layer, reveal in-plane magnetization with sharp and straight 90° and 180° domain walls that are expected in these alloys.

U2 - 10.1016/j.jmmm.2010.01.027

DO - 10.1016/j.jmmm.2010.01.027

M3 - Journal article

SN - 0304-8853

VL - 322

SP - 2023

EP - 2026

JO - Journal of Magnetism and Magnetic Materials

JF - Journal of Magnetism and Magnetic Materials

IS - 14

ER -