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Magnetic force microscope (MFM) tips are prepared by coating Fe(10 nm)/Co50Pt50(x nm)/Ru(5 nm) (at. %) films at 300 °C on Si-base tips of 4 nm radius. The thickness of CoPt layer, x, is varied in a range of 10 – 200 nm. The effects of coating thickness on spatial resolution and switching field of MFM tip are investigated. With increasing the thickness, the resolution deteriorates from 9.4 to 12.1 nm. The switching field increases from 0.675 to 2.025 kOe with increasing the coating thickness from 10 to 200 nm. A tip prepared by coating 100 nm thick Co50Pt50 film which has high resolution and high switching field property is successfully applied to the observation of magnetization structure of high-K u magnetic thin film with L10-ordered structure.

Co thin film were prepared on oxide single-crystal substrates of Al2O3(0001)D51, MgO(111)B1, and SrTiO3(111)E21 by ultra high vacuum molecular beam epitaxy. Effects of substrate material and substrate temperate on the film growth and the crystallographic properties were investigated. Co epitaxial thin films of hcp(0001) and/or fcc(111) orientations are obtained on all the substrate. With increasing the substrate temperature, the volume ratio of hcp to fcc increases for the Co films grown on Al2O3 and MgO substrates, whereas the ratio decrease for the Co film grown on SrTiO3 substrate. The in-plane lattice strain is larger than the out-of-plane strain due to accommodation of lattice mismatch between the film and the substrate

Magnetic force microscope (MFM) tips were prepared by coating commercial atomic force microscope (AFM) tips of 5 nm radius with Co and CoCrPt magnetic thin films varying the thickness in a range of 10?80 nm. The structural and the magnetic properties of coated magnetic thin films were investigated by scanning electron microscopy, AFM, X-ray diffraction, and vibrating sample magnetometry. The tip radius and the film surface roughness increase with increasing the film thickness. With increasing the film thickness, the MFM signal sensitivity increases, whereas the resolution decreases due to increase of tip radius. The MFM observation resolutions of 10 nm and 23 nm are obtained with the tips coated with 20-nm-thick Co and 40-nm-thick CoCrPt films, respectively. The MFM resolution is influenced by both the tip radius and the magnetic moment of coated material.

Permalloy (Py: Ni – 20 at. % Fe) thin films were prepared on MgO single-crystal substrates of (100), (110), and (111) orientations by molecular beam epitaxy. Py crystals consisting of fcc(100) and hcp(110) orientations epitaxially nucleate on MgO(100) substrates. With increasing the substrate temperature, the volume ratio of fcc(100) to hcp(110) crystal increases. The metastable hcp(110) structure transforms into more stable fcc(110) structure with increasing the film thickness. Py(110)fcc single-crystal films are obtained on MgO(110) substrates, whereas Py films epitaxially grow on MgO(111) substrates with two types of fcc(111) variants whose orientations are rotated around the film normal by 180° each other. X-ray diffraction analysis indicates that the out-of-plane and the in-plane lattice spacings of these fcc–Py films agree within ±0.4% with the values of bulk fcc–Py crystal, suggesting that the strains in the films are very small. High-resolution transmission electron microscopy shows that periodical misfit dislocations are preferentially introduced in the films around the Py/MgO(100) and the Py/MgO(110) interfaces to reduce the lattice mismatches. The magnetic properties are considered to be reflecting the magnetocrystalline anisotropies of bulk fcc–Py and/or metastable hcp–Py crystals and the shape anisotropy caused by the surface undulations.

Fe, Fe50Co50, and Fe80Ni20 (at. %) single-crystal films with the (100)bcc plane parallel to the substrate surface were prepared on MgO(100) single-crystals heated at 300 °C by ultra high vacuum molecular beam epitaxy. The film growth mechanism, the film structure, and the magnetic properties were investigated. In-situ reflection high energy electron diffraction and X-ray diffraction analyses indicate that the strains in the films are very small though there are fairly large mismatches of −3.7~−4.3% at the film/substrate interface. Cross-sectional high-resolution transmission electron microscopy shows that misfit dislocations are introduced in the film at the interface. Dislocations are also observed in the film up to around 10~20 nm distance from the interface. The presence of such dislocation relieves the strain caused by the lattice mismatch. The in-plane magnetization properties of these films reflect the magnetocrystalline anisotropies of respective bulk Fe, Fe50Co50, and Fe80Ni20 crystals.

Ni epitaxial films are prepared by ultra-high vacuum rf magnetron sputtering on Cr underlayers of (100) and (211) planes grown hetero-epitaxially on MgO substrates of (100) and (110) orientations, respectively. The film growth behavior and the crystallographic properties are studied by in-situ reflection high energy electron diffraction and pole figure X-ray diffraction. Metastable hcp-Ni(110) and hcp–Ni(100) crystals respectively nucleate on Cr(100) and Cr(211) underlayers, where the hcp crystals are stabilized through hetero-epitaxial growth. With increasing the film thickness, the hcp structure in the Ni films starts to transform into more stable fcc structure by atomic displacement parallel to the hcp(0001) closed packed plane. The resulting films consist of hcp and fcc crystals.

A Ni epitaxial film with hcp(1100) single-crystal structure is obtained on a Cr(211) underlayer hetero-epitaxially grown on an MgO(110) single-crystal substrate in an early stage of film growth by ultra high vacuum rf magnetron sputtering. Reflection high energy electron diffraction (RHEED) observation indicates that the metastable hcp-Ni crystal tends to transform into more stable fcc crystal with increasing the film thickness. The crystallographic orientation relationship between the hcp and the fcc crystals is determined by RHEED and - scan X-ray diffraction. High-resolution transmission electron microscopy shows that the hcp and the fcc crystals exist separately on the Cr underlayer. The lattice constants of hcp-Ni crystal are determined from X-ray diffraction analysis as a=0.249 nm, c=0.415 nm, and c/a=1.67.

Fe thin films, down to 6 nm thick, were prepared on GaAs(001) substrates by RF magnetron sputtering. The x-ray diffraction (XRD) analyses show that the epitaxial thin films of Fe(001) were grown with cube-on-cube orientation on GaAs(001). Magnetic properties were investigated by vibrating sample magnetometry (VSM) and ferromagnetic resonance (FMR) spectroscopy. The magnetization curves obtained by applying in-plane magnetic fields indicate that easy (hard) direction is along [100] ([110]) and the saturation magnetization is close to the bulk values. The in-plane magnetic anisotropy measured by FMR shows four-fold symmetry, as expected for bcc Fe. We did not observe the in-plane uniaxial magnetic anisotropy reported on the MBE-grown Fe films on GaAs substrates.

Co epitaxial thin films were prepared on Al2O3(0001) single-crystal substrates in a substrate temperature range between 50 and 500 °C by ultra high vacuum molecular beam epitaxy. Effects of substrate temperature on the structure and the magnetic properties of the films were investigated. The films grown at temperatures lower than 150 °C consist of fcc- Co(111) crystal. With increasing the substrate temperature, hcp-Co(0001) crystal coexists with the fcc crystal and the volume ratio of hcp to fcc crystal increases. The films prepared at temperatures higher than 250 °C consist primarily of hcp crystal. The film growth seems to follow island-growth mode. The films consisting primarily of hcp crystal show perpendicular magnetic anisotropy. The domain structure and the magnetization properties are influenced by the magnetocrystalline anisotropy and the shape anisotropy caused by the film surface roughness.

Co(110) epitaxial thin films with hcp structure were prepared on MgO(100) single-crystal substrates heated at 300 °C by ultra high vacuum molecular beam epitaxy. The microstructure is investigated by employing X-ray diffraction and high-resolution transmission electron microscopy. The film consists of two types of domains whose c-axes are rotated around the film normal by 90° each other. Stacking faults are observed for the film along the Co[0001] direction. An atomically sharp boundary is recognized between the film and the substrate, where some misfit dislocations are introduced in the film at the Co/MgO interface. Dislocations are also observed in the film up to 15 nm thickness from the interface. Presence of such stacking faults and misfit dislocations seem to relieve the strain caused by the lattice mismatch between the film and the substrate. X-ray diffraction analysis indicates that the out-of-plane and the in-plane lattice spacings of the film are in agreement within 0.5% and 0.1%, respectively, with those of the bulk hcp–Co crystal, suggesting the strain in the film is very small.

SmFe5(0001) single-crystal thin films are prepared by molecular beam epitaxy employing Cu(111) single-crystal underlayers on MgO(111) substrates. The Cu atoms diffuse into the Sm-Fe layer and substitute the Fe sites in SmFe5 structure forming an alloy compound of Sm(Fe,Cu)5. The Sm(Fe,Cu)5 film is more Cu enriched with increasing the substrate temperature. The Cu underlayer plays an important role in assisting the formation of the ordered phase.

Ni epitaxial films with an hcp structure are successfully obtained on Au(100) single-crystal underlayers formed on MgO(100) substrates at temperatures lower than 300 °C by molecular beam epitaxy. With increasing the substrate temperature, the volume ratio of more stable fcc phase inc_reases in the film. The Ni film prepared at 100 °C consists primarily of hcp crystal with the (110) plane parallel to the substrate surface coexisting with a small amount of fcc–Ni(100) crystal. The lattice constant of hcp-Ni crystal is determined as a = 0.249 nm, c = 0.398 nm, and c/a = 1.60.