Temperature Dependence of the Texture of Sm-Co Thin Films

Physica Status Solidi (a)

Rao

Fähler

et al. 2010

Self Cite

The crystallographic and magnetic texture of epitaxial, hard magnetic Sm2Co7 films prepared on Cr‐buffered MgO single‐crystal substrates are analyzed. Substrate symmetry, deposition temperature, and deposition rate are systematically varied, resulting in a variety of different, but epitaxial orientations. On Cr‐buffered MgO(001), Sm2Co7 grows with three different types of orientations: one inplane orientation with the c‐axis aligned in the substrate plane parallel to MgO[100] and [010], and two tilted orientations, where the c‐axes of the Sm2Co7 crystals have a 45° and 60° orientation to the substrate plane. The volume fraction of the tilted orientations decreases with decrease in the Sm2Co7 deposition temperature. A lower limit is given by the epitaxial growth temperature, which is necessary to form a fully crystalline, epitaxial film. This temperature can be reduced by lowering the deposition rate. Thus, almost completely inplane aligned films can be achieved by a low‐rate/low‐temperature deposition. On a Cr‐buffered MgO(011) substrate Sm2Co7 grows with a single orientation, i.e., with the c‐axis aligned onto the substrate plane parallel to MgO[100]. The findings are discussed considering elastic strain minimization, thermodynamics and kinetics of film growth, surface faceting, and Co‐particle formation.

Section: Resultssupporting

confidence: 65%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

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Section: Introductionmentioning

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Texture formation in epitaxial hard magnetic Sm₂Co₇ thin films

Physica Status Solidi (a)

Rao

Fähler

et al. 2010

Self Cite

Epitaxial growth of highly coercive Sm–Co thin films using pulsed laser deposition

Singh

Journal of Applied Physics

Neu

et al. 2005

Hard magnetic materials with a uniaxial magnetocrystalline anisotropy can be most efficiently used if the easy axis is well aligned along one crystallographic direction in the entire sample volume. Epitaxial growth is one suitable method to achieve this aim and therefore Sm–Co thin films on Cr-buffered single-crystal MgO (100) substrates were deposited. Pulsed laser deposition from elemental Sm and Co targets was used to prepare films of nominal Sm2Co7 stoichiometry. Pole figure measurements and magnetization measurements reveal an epitaxial growth of Cr on MgO onto which the c axis of the Sm–Co layer is aligned in plane, viz., MgO(001)[100]‖Cr(001)[110]‖Sm–Co(110)[001]. At higher deposition temperatures an additional Sm–Co (1 1 16) texture was observed. This corresponds to an additional epitaxial orientation relation, where the c axis is tilted 60° out of the substrate plane. However, at low deposition temperatures and with smaller pulse repetition rates a reduction in the amount of this unwanted component can be achieved. This leads to the orientation of the c axis, which is the easy magnetization axis, only along two equivalent MgO [100] directions in the substrate plane. The resulting magnetic anisotropy has been confirmed by hysteresis measurements along three nonequivalent directions where high remanences and a high coercivity of up to 2.4T along MgO [110] can be achieved.

Growth of epitaxial SmCo5 films on Cr∕MgO(100)

Singh

Neu

Applied Physics Letters

et al. 2005

Although the hard magnetic SmCo5 phase has very attractive and well-known intrinsic magnetic properties, it has not been grown as an epitaxial thin film, so far. This letter reports the epitaxial growth of SmCo5 films by pulsed-laser deposition on Cr(100) buffered MgO(100) single-crystal substrates. The phase purity, crystal structure, epitaxial relation to the substrate, and magnetic properties have been determined by careful energy-dispersive x-ray analysis, pole figure measurements, transmission electron microscopy, and vibrating sample magnetometry. Compared to the formerly studied Sm2Co7 films, the preparation of the SmCo5 phase improves the remanent magnetization by 38%.