CrPt 3 thin film media for perpendicular or magneto-optical recording

Abstract

The magnetic properties of CrPt 3 L1 2 ferrimagnetic thin films have been studied. Films were produced by sputtering multilayers of Cr and Pt onto silicon nitride coated silicon substrates. The as-deposited films are nonmagnetic. An anneal at ϳ800°C results in ferrimagnetic behavior with a perpendicular easy-axis. X-ray diffraction and transmission electron microscopy ͑TEM͒ measurements show that ͑111͒ CrPt 3 is the only crystalline phase present after annealing. Rocking curves with a full width at half maximum as low as 1.8°indicate good crystallographic orientation. Magnetic properties of the films vary with composition, annealing temperature and time, layer thickness, and sputtering conditions. The films exhibit large coercivities, H c , that can be tuned in the range 1500-8000 Oe. Saturation magnetization, M s , is typically 150-200 emu/cc. Squarenesses, S, as high as 0.99 have been found. A uniaxial magnetic anisotropy constant, K u , of up to 8ϫ10 6 erg/cc was achieved. TEM micrographs show a 35 nm average grain size and complete interdiffusion of the Cr and Pt. Magneto-optical hysteresis loops at 632.8 nm wavelength reveal Kerr rotations of about 0.21°when the films are overcoated with a quarter-wavelength dielectric.

Magnetic anisotropy of MBE grown MnPt3 and CrPt3 ordered alloy films

“…The CrPt 3 and MnPt 3 films show the spectral shape of the Kerr rotation similar to each other, while they showed quite different magnetic anisotropy. The CrPt 3 film exhibits a large perpendicular anisotropy [2,3], while the MnPt 3 film has the easy axis parallel to the film plane [1]. CrPt 3 and MnPt 3 ordered alloys are known to have the same crystal structure of Cu 3 Au type.…”

“…CrPt 3 and MnPt 3 ordered alloys exhibit large magneto-optical Kerr rotations of À0.7 and À1.2 , respectively, at a photon energy around 1.2 eV [1,2]. The CrPt 3 and MnPt 3 films show the spectral shape of the Kerr rotation similar to each other, while they showed quite different magnetic anisotropy.…”

“…CrPt 3 and MnPt 3 alloy films were deposited directly onto MgO(1 1 1), Al 2 O 3 (0 0 1 c), and fused quartz substrates. The substrates were kept at 600 C during the growth, and the films were post-annealed at 850 C for CrPt 3 and at 800 C for MnPt 3 . The film structure was characterized by X-ray diffraction (XRD).…”

Self-assembling of alloy nanostructures on van der Waals surfaces

“…Surprisingly, such nanostructured films grown at room temperature exhibit perpendicular magnetic anisotropy, which disappears as soon as the deposition temperature is increased above 100 C favoring the development of L1 2 longe-range ordering in the FCC lattice. Here we present the growth of the ferrimagnetic CrPt 3 and ferromagnetic FePt alloys which owing to their magnetocrystalline anisotropy are also good candidates for magnetic recording media [3][4][5], and also that of the VPt 3 alloy which owing to the expected reduced size of the nanostructures could favor the formation of the still controversial ferrimagnetic L1 2 phase [6].…”

Μελέτη Των Μαγνητικών Ιδιοτήτων Και Αλληλεπιδράσεων Ανταλλαγής Σε Νανοσύνθετα Μαγνητικά Υλικά

“…Αυτό αποδίδεται σε μία κατ' ασυνήθιστο τρόπο ισχυρή υβριδοποίηση του χρωμίου 3d-πλατίνας 5d, δίνοντας μία τροχιακή μαγνητική ροπή 0,15 μ B στο χρώμιο που είναι παράλληλο στη μαγνητική ροπή του σπιν των 2,72 μ B 254. Επίσης οι φάσεις καταδεικνύουν ισχυρά μαγνητο-οπτικά φαινόμενα 257. Εκτός από τα καθαρά κράματα οι περισσότερες έρευνες έχουν εστιαστεί στα λεπτά υμένια 257,258.…”