Download or read book Influence of Thickness on Magnetic Transitions of Heavy Rare Earth Thin Films written by Shibaji Saha and published by . This book was released on 1993 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Influence of Structure on Magnetic Properties of Transition Metal and Rare Earth Thin Films written by William Allen Lewis and published by . This book was released on 1994 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of High Pressure on Magnetic Transitions in Heavy Rare Earth Metals written by Sarah A. Thomas and published by . This book was released on 2013 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A study on structural inhomogeneity and magnetic properties of rare earth transition metal compositionally modulated thin films written by Geon Choe and published by . This book was released on 1989 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Novel Magnetic Behavior in Heavy Rare Earth Superlattices written by Tien Fang Tsui and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Structural and magnetic properties of heavy rare earth films and superlattices synthesized by molecular beam epitaxy are investigated. Epitaxial films of rare earth metals, and superlattices of rare earths with Y interlayers, are grown along different hcp orientations using novel techniques developed specifically for this thesis research. Interesting growth patterns and surface reconstructions are observed, particularly on the a and b faces of the hcp material. Magnetic behavior is explored by neutron diffraction and SQUID magnetometry experiments. The spatial form of the exchange interaction is explored by probing the dependence of magnetic coherence on crystal growth orientation. The results reveal that Dy/Y and Gd/Y superlattices grown along the a and b axis exhibit weak magnetic coupling between successive magnetic layers, even for nonmagnetic spacers as thin as $sim$20 A. Previous studies of the c-axis materials established that long range magnetic order occurs even through Y spacer layers as thick as $sim$120 A. This measured anisotropy between behavior along the c-axis and perpendicular to it, is over a factor ten in both the coupling strength and the range. The strongly anisotropic coupling behavior is shown to have its origin in nearly 2-dimensional nesting features of the rare earth Fermi surfaces. Nesting along the c-axis gives rise to long range exchange interactions along the c-axis, and the lack of nesting perpendicular to the c-axis leaves a rapid exponential decay of the exchange with spin separation. Magnetic phases of epitaxial Dy films are examined as a function of epitaxial strain, growth orientation, temperature and field. The analysis of the observed anisotropic magnetoelastic behavior reveals the detailed energy balance in the Dy system. The observed spin configurations in thin Gd films show that the magnetocrystalline anisotropy of bulk Gd is substantially modified in the films. This in turn gives insight into the origin of the unusual spin reorientation transition in Gd. Magnetic order in buried monolayers of Gd-Y alloys is studied in order to explore the effects of both the reduced physical dimensions and the modified effective exchange interaction on phase transitions. No long range order occurs in the monolayer system even for nearly full Gd monolayer coverage. A spin-glass transition is observed instead. The zero field susceptibility exhibits a divergence at low temperatures. The analysis of the magnetic states reveals unusual scaling behavior and a dimensionality cross-over in the monolayer system.
Download or read book The physics of thermomagnetic recording in thin films of rare earth transition metal alloys written by Robert Shaw-Tzuu Weng and published by . This book was released on 1991 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Magnetic Thin Film Research written by and published by . This book was released on 1996 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work in the past year has primarily involved four areas of magnetic thin films: amorphous rare earth-transition metal alloys, epitaxial CoPt3 and Ni-Pt alloy thin films, amorphous rare earth doped Si (a new class of dilute magnetic semiconductor with large negative magnetoresistance which the authors have discovered), and exchange-coupled antiferromagnetic insulators. In the amorphous alloys, they made a systematic study of the effects of local anisotropy, macroscopic (up tack) anisotropy, and exchange constant on the fundamental (and practical) properties of these magnetic alloys, as originally described in the grant proposal. The work on the epitaxial Co-Pt (and more recently Ni-Pt) alloys was originally undertaken as a comparison study to the amorphous alloys. Crystalline Co-Pt alloys have many striking similarities to the amorphous rare earth-transition metal alloys: perpendicular magnetic anisotropy, magneto-optic activity, and a {Tc} (for CoPt3) somewhat above room temperature. They have discovered that these alloys exhibit a remarkable new phenomena; a surface-induced miscibility gap in a material which is believed to be completely miscible in the bulk. The authors are currently in several collaborations to measure specific heat of magnetic thin films. They used the specific heat to study antiferromagnetic superlattices, specifically NiO, CoO and MgO in various combinations to allow separation of effects of finite layer thickness and exchange coupling on the magnetic ordering.
Download or read book Rare Earth Permanent Magnet Alloys High Temperature Phase Transformation written by Shuming Pan and published by Springer. This book was released on 2014-12-01 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: The process of high temperature phase transition of rare earth permanent-magnet alloys is revealed by photographs taken by high voltage TEM. The relationship between the formation of nanocrystal and magnetic properties is discussed in detail, which effects alloys composition and preparation process. The experiment results verified some presumptions, and were valuable for subsequent scientific research and creating new permanent-magnet alloys. The publication is intended for researchers, engineers and managers in the field of material science, metallurgy, and physics. Prof. Shuming Pan is senior engineer of Beijing General Research Institute of Non-ferrous Metal.
Download or read book Growth Induced Magnetic Anisotropy in Amorphous Thin Films Annual Progress Report Year 1 November 4 1994 October 31 1995 written by and published by . This book was released on 1995 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work in the past year has primarily involved three areas of magnetic thin films: amorphous rare earth-transition metal alloys, epitaxial COPt3 thin films, and exchange coupled antiferromagnetic insulators. In the amorphous alloys, the authors have focused on understanding the cause and the effect of the growth-surface-induced perpendicular magnetic anisotropy. Using the results of previous work, they are able to control this anisotropy quite precisely. This anisotropy is predicted to have dramatic and as-yet unobserved effects on the underlying nature of the magnetism. The work on the epitaxial Co-Pt alloys was originally undertaken as a comparison study to the amorphous alloys. The authors have discovered that these alloys exhibit a remarkable new phenomena; a surface-induced miscibility gap in a material which is believed to be completely miscible in the bulk. This miscibility gap is 100% correlated with the perpendicular anisotropy, although the connection is not yet clear, and is presumably linked to a magnetic energy of mixing which tends to drive a material towards clustering. The problem of exchange coupling in multilayers impacts many of the current research areas in magnetism. NiO/CoO multilayers can be prepared with coherent interfaces. The specific heat shows unambiguously the ordering of the spins in the layers. The results show clearly the transition from a single transition temperature to two distinct transitions with increasing thickness of the individual layers. From this data, the authors are able to determine the interface magnetic exchange coupling constant and the effect on the transition temperature of finite layer thickness.
Download or read book Growth of Oriented Rare earth transition metal Thin Films written by and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preparation and Characterization of Amorphous Transition Metal rare Earth Thin Films written by Philip Richard Frausto and published by . This book was released on 1988 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Magnetooptical Spectroscopy of the Rare Earth Compounds Development and Application written by Uygun V. Valiev and published by Scientific Research Publishing, Inc. USA. This book was released on 2012-01-05 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comparison of theory with experiment is made for rare-earth compounds with garnet structure and orthoaluminate whose optical, magnetic and magnetooptical features have been studied sufficiently well by now.
Download or read book Magneto optical Studies of Exchange coupled Rare Earth transition Metal Thin Films written by Raju Rishi and published by . This book was released on 1990 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metals Abstracts written by and published by . This book was released on 1994 with total page 1584 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976 with total page 680 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigations of the Epitaxial Growth and Characterization of High Perfection Magnetic Thin Films written by and published by . This book was released on 1991 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: Methods of preparing high-perfection single crystalline films of 3d elements (including Fe, Co) and magnetic rare earths on semiconducting GaAs substrates have been investigated. The use of seed layers of Fe or Co (a few monolayers thick), deposited onto GaAs(001), followed by a Ag(001) film, provided a suitable template for Fe epitaxy. This method avoided interfacial chemical reactions between Fe and the semiconductor, at the expense of introducing coherency strain and tilted epitaxy of the Fe. In the case of rare earths, intermediate seed films of rare earth trifluorides, grown onto GaAs(111(-)) provided a template for growth of c-axis oriented rare earth films and sandwich structures. These methods have enabled the effects of coherency strain on magnetic properties of Fe and rare earths to be investigated. Using an automated X-ray photoelectron diffraction (XPD) system we have investigated the growth and interfacial mixing of several key epitaxial systems including Co/Pt, Co/Ag, NdF3/LaF3 and Pt/GaAs. Interfacial mixing in the interfaces of Co/Pt superlattices was confirmed, resulting in an alloyed region containing the ordered L12 phase: CoPt3. Spin-polarized photoelectron diffraction (SPPD) experiments on MnF2 suggest a new , high-temperature magnetic ordering transition at 380K which is 313K above the Neel temperature.
