Magnetic-field-modulated written bits in TbFeCo thin films: Transmission electron microscopy Lorentz and scanning electron microscopy with polarization analysis studies
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (USA) Greidanus, F.J.A.M. (Philips Research Laboratories, P.O. Box 80.000, 5600 JA, Eindhoven (The Netherlands))
Domains written thermomagnetically in TbFeCo thin films are studied with Lorentz transmission electron microscopy (TEM) and scanning electron microscopy with polarization analysis (SEMPA). Four different rare-earth/transition-metal compositions Tb{sub {ital x}}Fe{sub {ital y}}Co{sub 1{minus}{ital x}{minus}{ital y}} are examined. The domain structures observed with both techniques are similar even though TEM Lorentz only detects the transverse component of the net magnetic field along the electron's trajectory through the sample, while SEMPA detects the surface electron-spin polarization (magnetization). We find that the magnetic contrast in the SEMPA measurements is proportional to the magnetization of the transition-metal (TM) subnetwork which is antiferromagnetically coupled to the rare-earth (RE) subnetwork. This allows high-contrast SEMPA images to be acquired even when the system is magnetically compensated ({ital M}{sub {ital s}}={vert bar}{ital M}{sub RE}{minus}{ital M}{sub TM}{vert bar}=0). The surface magnetization can be explained by assuming that the surface of the TbFeCo alloy consists of an outermost thin oxide layer followed by an Fe-rich subsurface layer. The importance of the demagnetizing field on the switching and domain nucleation process for thermomagnetically written bits is examined.
- OSTI ID:
- 6086283
- Journal Information:
- Journal of Applied Physics; (USA), Vol. 68:9; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
Similar Records
The influence of the pregroove on the shape of thermomagnetically written domains
Lorentz microscopy on dynamically written domains in GdTbFe