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Mossbauer effect studies on magnetic thin films
Classified
abstracts
352-361
vacuum and cathodic sputtering. It is found that the films prepared on cold substrates have low resistivity of 0.01 to 10 ohm cm and they show practically no photosensitivity. Low resistivity is due to an excess of Cd in the films. With increasing substrate temperature, resistivity increases by several orders of magnitude and the films become photosensitive. Thermal treatment of these films at 500°C and above this temperature with duration of 40 to 100 minutes results in significant decrease of their resistivity and complete loss of their photosensitivity. Single crystal Cd&Se,-, films grow on freshly cleaved mica at 250°C and the average growth rate of 100 Ajmin. It is found that resistivitv of CdS,Se,_, films increases with reduction of their thickness. _ N I Dovgoshey et al, Semiconductor 1971, 71-85 (in Russian). 352. Influence of preparation
Electronics,
Collection,
Uzhorod
methods on structure of CdS,Se,_,
30 films.
(USSR) Using the methods of transmission and reflection electron diffraction, structure of films of CdS-CdSe solid solutions is investigated in the entire interval of their composition. The CdS,Se,, films w&e evaporated in vacuum on structure-less substrates such as collodium, carbon and fused silica and single crystal substrates such as mica and NaCl both cold and heated. It is found that depending on the crystallization conditions, both mono-phase, cubic or hexagonal and multi-phase films are formed. The (111) face of cubic phase or (0001) face of hexagonal phase are usually oriented in a parallel direction to the substrate. 1 A Gryadil and N I Dovgoshey, Semiconductor Electronics, Collection, Uzhorod
1971, 86-96 (in Russian).
353. Quality of films obtained by thermal evaporation barium-borosilicate glasses. (USSR)
in vacuum
30 of
It is shown that properties of films with optimum composition, obtained by flash evaporation glass powder, are similar to the properties of bulk glass. The films differ in the enhanced defect concentration and oxygen deficit. Structure can be improved and electrical properties controlled by annealing of the films in air and introduction of the proper additives. Infrared absorption spectra and dependences of breakdown voltage on thickness are measured. Introducing BaO in the films, the dielectric constant linearly increases up to 6. I N Vozhenin et al, Electronic Technology, Scient-Techn Collect, Control of Quality and Standardization, No 1, 1971, 84-90 (in Russian). 30 354. Magnetic
oxide films.
(Czechoslovakia) Magnetic oxide films including europium oxide, yttrium and gadolinium iron garnets, orthoferrites, and ferrites are reviewed from a point of view which stresses the common aspects of oxide film growth and the resulting structural and magnetic properties. The interest in producing these films has been motivated by their possible application in microwave devices, magneto-optic memories and most recently in cylindrical domain memories. The growth techniques of each material are described. They include chemical vapour deposition, sputtering, chemical solution, liquid epitaxy, and vacuum evaporation. Problems such as non-stoichiometry, strain, cracking, and substratefilm interaction are discussed for each material. The substrate is found to exert a strong influence on the film quality and generally a better match between film and substrate results in improved films. The magnetic characteristics of the films including the magnetization, coercive force, Faraday rotation, and ferromagnetic resonance linewidth are discussed. In terms of these properties, the films are compared with the corresponding bulk materials. The means of improving magnetic oxide films are considered, and an assessment is made of the possibility of producing thin films whose structural and magnetic properties are comparable with those of bulk material. R M Josephs and B F Stein, Czech JPhys, B 21 (4/5), 1971, 351-367. 355. Elastic
tension
effect on magnetic
properties
30 of ferromagnetic
films. (Czechoslovakia) Influence of mechanical stresses on the processes of quasi-static magnetization reversal, the dynamic characteristics and the creep of the domain walls of Fe-Ni films with Ni content from 60 to 90 per cent and the thickness from 150 to 3000 8, is investigated. The films 118
have been obtained by thermal evaporation of Fe-Ni alloys in vacuum on glass substrates at 200 to 250°C. V A Bouravikhin and V G Kazakov, Czech J Phys, B 21 (4/5), 1971, 375-383. 356. Mossbauer
30 effect studies on magnetic thin films. (Czechoslovakia)
The particular possibilities and experimental difficulties, which arise in applications of the Mossbauer method to thin film problems, are discussed. The main results of the so far rather scarce Mossbauer studies of magnetic thin films are reviewed. Preparation of a thin film Mossbauer absorber by vacuum deposition of enriched 67Fe layers separated by SiO or MgFe layers is described. W Zinn, Czech J Phys, B 21 (4/5), 1971, 391406. 357. Dynamic formation of diffuse boundaries and quasi-static growth in magnetic thin films. (Czechoslovakia)
30 domain
Using photographs obtained with a 10 nsec exposure time Kerr magneto-optic camera, the dynamic and quasi-static growth of reverse domains from nucleation centres at the edge of magnetic thin films have been studied and compared. The magnetic film used was vacuum evaporated from a melt of 83 per cent Ni-17 per cent Fe onto a glass substrate at 250°C in vacuum of 10-8,torr in the presence of a uniform magnetic field in the plane of the substrate. Experimental results are discussed. M H Kryder and F B Humphrey, 457459.
Czech J Phys,
B 21 (4/5), 1971,
30 358. Measurements of the mobility of domain walls in permalloy films in a wide thickness range. (Czechoslovakia)
The mobility of domain walls in permalloy films has been measured with the aid of the Kerr effect. Permalloy films with thickness in the range of 150 A to 5.6 ,um have been deposited in vacuum 10m5torr. Experimental results are discussed. E N Ilyicheva et al, Czech J Phys, B 21 (4/5), 1971, 460-463. 30 359. Exchange
coupling
between
two
permalloy
films for various
interface treatments. (Czechoslovakia) Using the standing spin wave resonances, the exchange coupling between two permalloy films in intimate contact is studied for various treatments of the first film. Experimental investigations were performed on specimens prepared by the successive evaporation of the two layers in an ultrahigh vacuum system at 10Ts torr. After only a vacuum exposure of the first film, the coupling is shown to be complete, after an air exposure and various vacuum treatments (2OOC, 270°C 32o”C), the coupling increases. These results are well explained by low-energy electron diffraction studies on oxygen adsorption and oxide formation on nickel and iron surfaces. Annealing of the composite films shows that the coupling is varied only above 600°C indicating that the oxygen at the interface is firmly bound. H Pascard and F Hoffman, Czech J Phys, B 21 (4/5), 1971, 4788481. 360. Temperature
30 dependence of SSW linewidth in metallic thin films.
(Czechoslovakia) Measurements of the standing spin wave linewidth at 17.6 GHz from 6°K to 400°K are performed for two permalloy films. The first film with a thickness of 3600 8, had a polycrystalline structure and was deposited at lo-* torr on a glass substrate heated to 220°C at a deposition rate of 9 A/set. The second film was epitaxially deposited in vacuum on a gold-coated mica substrate. It is found that in highquality permalloy films, the standing spin wave linewidth is little modified by temperature variation in the examined range. A J Berteaud and A Stankoff, Czech J Phys, B 21 (4/5), 1971,486489. 30 361. New experiments
on the origin of anisotropy
in permalloy
films.
(Czechoslovakia) A series of new experiments has been performed to determine the origin of the uniaxial anisotropy in permalloy films. By means of a double magnetic shield enclosing the vacuum system, it was possible to deposit films in extremely small ambient fields of 10eB to 10e3 oersted. The deposition system was of the vat-ion variety with a base pressure of 3 x lo-” torr. It is found that at deposition field strengths below 10-l oersted, both the anisotropy and squareness of the loop decreases dramatically. From these experimental results, it appears
abstracts
352-361
vacuum and cathodic sputtering. It is found that the films prepared on cold substrates have low resistivity of 0.01 to 10 ohm cm and they show practically no photosensitivity. Low resistivity is due to an excess of Cd in the films. With increasing substrate temperature, resistivity increases by several orders of magnitude and the films become photosensitive. Thermal treatment of these films at 500°C and above this temperature with duration of 40 to 100 minutes results in significant decrease of their resistivity and complete loss of their photosensitivity. Single crystal Cd&Se,-, films grow on freshly cleaved mica at 250°C and the average growth rate of 100 Ajmin. It is found that resistivitv of CdS,Se,_, films increases with reduction of their thickness. _ N I Dovgoshey et al, Semiconductor 1971, 71-85 (in Russian). 352. Influence of preparation
Electronics,
Collection,
Uzhorod
methods on structure of CdS,Se,_,
30 films.
(USSR) Using the methods of transmission and reflection electron diffraction, structure of films of CdS-CdSe solid solutions is investigated in the entire interval of their composition. The CdS,Se,, films w&e evaporated in vacuum on structure-less substrates such as collodium, carbon and fused silica and single crystal substrates such as mica and NaCl both cold and heated. It is found that depending on the crystallization conditions, both mono-phase, cubic or hexagonal and multi-phase films are formed. The (111) face of cubic phase or (0001) face of hexagonal phase are usually oriented in a parallel direction to the substrate. 1 A Gryadil and N I Dovgoshey, Semiconductor Electronics, Collection, Uzhorod
1971, 86-96 (in Russian).
353. Quality of films obtained by thermal evaporation barium-borosilicate glasses. (USSR)
in vacuum
30 of
It is shown that properties of films with optimum composition, obtained by flash evaporation glass powder, are similar to the properties of bulk glass. The films differ in the enhanced defect concentration and oxygen deficit. Structure can be improved and electrical properties controlled by annealing of the films in air and introduction of the proper additives. Infrared absorption spectra and dependences of breakdown voltage on thickness are measured. Introducing BaO in the films, the dielectric constant linearly increases up to 6. I N Vozhenin et al, Electronic Technology, Scient-Techn Collect, Control of Quality and Standardization, No 1, 1971, 84-90 (in Russian). 30 354. Magnetic
oxide films.
(Czechoslovakia) Magnetic oxide films including europium oxide, yttrium and gadolinium iron garnets, orthoferrites, and ferrites are reviewed from a point of view which stresses the common aspects of oxide film growth and the resulting structural and magnetic properties. The interest in producing these films has been motivated by their possible application in microwave devices, magneto-optic memories and most recently in cylindrical domain memories. The growth techniques of each material are described. They include chemical vapour deposition, sputtering, chemical solution, liquid epitaxy, and vacuum evaporation. Problems such as non-stoichiometry, strain, cracking, and substratefilm interaction are discussed for each material. The substrate is found to exert a strong influence on the film quality and generally a better match between film and substrate results in improved films. The magnetic characteristics of the films including the magnetization, coercive force, Faraday rotation, and ferromagnetic resonance linewidth are discussed. In terms of these properties, the films are compared with the corresponding bulk materials. The means of improving magnetic oxide films are considered, and an assessment is made of the possibility of producing thin films whose structural and magnetic properties are comparable with those of bulk material. R M Josephs and B F Stein, Czech JPhys, B 21 (4/5), 1971, 351-367. 355. Elastic
tension
effect on magnetic
properties
30 of ferromagnetic
films. (Czechoslovakia) Influence of mechanical stresses on the processes of quasi-static magnetization reversal, the dynamic characteristics and the creep of the domain walls of Fe-Ni films with Ni content from 60 to 90 per cent and the thickness from 150 to 3000 8, is investigated. The films 118
have been obtained by thermal evaporation of Fe-Ni alloys in vacuum on glass substrates at 200 to 250°C. V A Bouravikhin and V G Kazakov, Czech J Phys, B 21 (4/5), 1971, 375-383. 356. Mossbauer
30 effect studies on magnetic thin films. (Czechoslovakia)
The particular possibilities and experimental difficulties, which arise in applications of the Mossbauer method to thin film problems, are discussed. The main results of the so far rather scarce Mossbauer studies of magnetic thin films are reviewed. Preparation of a thin film Mossbauer absorber by vacuum deposition of enriched 67Fe layers separated by SiO or MgFe layers is described. W Zinn, Czech J Phys, B 21 (4/5), 1971, 391406. 357. Dynamic formation of diffuse boundaries and quasi-static growth in magnetic thin films. (Czechoslovakia)
30 domain
Using photographs obtained with a 10 nsec exposure time Kerr magneto-optic camera, the dynamic and quasi-static growth of reverse domains from nucleation centres at the edge of magnetic thin films have been studied and compared. The magnetic film used was vacuum evaporated from a melt of 83 per cent Ni-17 per cent Fe onto a glass substrate at 250°C in vacuum of 10-8,torr in the presence of a uniform magnetic field in the plane of the substrate. Experimental results are discussed. M H Kryder and F B Humphrey, 457459.
Czech J Phys,
B 21 (4/5), 1971,
30 358. Measurements of the mobility of domain walls in permalloy films in a wide thickness range. (Czechoslovakia)
The mobility of domain walls in permalloy films has been measured with the aid of the Kerr effect. Permalloy films with thickness in the range of 150 A to 5.6 ,um have been deposited in vacuum 10m5torr. Experimental results are discussed. E N Ilyicheva et al, Czech J Phys, B 21 (4/5), 1971, 460-463. 30 359. Exchange
coupling
between
two
permalloy
films for various
interface treatments. (Czechoslovakia) Using the standing spin wave resonances, the exchange coupling between two permalloy films in intimate contact is studied for various treatments of the first film. Experimental investigations were performed on specimens prepared by the successive evaporation of the two layers in an ultrahigh vacuum system at 10Ts torr. After only a vacuum exposure of the first film, the coupling is shown to be complete, after an air exposure and various vacuum treatments (2OOC, 270°C 32o”C), the coupling increases. These results are well explained by low-energy electron diffraction studies on oxygen adsorption and oxide formation on nickel and iron surfaces. Annealing of the composite films shows that the coupling is varied only above 600°C indicating that the oxygen at the interface is firmly bound. H Pascard and F Hoffman, Czech J Phys, B 21 (4/5), 1971, 4788481. 360. Temperature
30 dependence of SSW linewidth in metallic thin films.
(Czechoslovakia) Measurements of the standing spin wave linewidth at 17.6 GHz from 6°K to 400°K are performed for two permalloy films. The first film with a thickness of 3600 8, had a polycrystalline structure and was deposited at lo-* torr on a glass substrate heated to 220°C at a deposition rate of 9 A/set. The second film was epitaxially deposited in vacuum on a gold-coated mica substrate. It is found that in highquality permalloy films, the standing spin wave linewidth is little modified by temperature variation in the examined range. A J Berteaud and A Stankoff, Czech J Phys, B 21 (4/5), 1971,486489. 30 361. New experiments
on the origin of anisotropy
in permalloy
films.
(Czechoslovakia) A series of new experiments has been performed to determine the origin of the uniaxial anisotropy in permalloy films. By means of a double magnetic shield enclosing the vacuum system, it was possible to deposit films in extremely small ambient fields of 10eB to 10e3 oersted. The deposition system was of the vat-ion variety with a base pressure of 3 x lo-” torr. It is found that at deposition field strengths below 10-l oersted, both the anisotropy and squareness of the loop decreases dramatically. From these experimental results, it appears