摘要:

A Sm2.48Lu0.26(Pb,Pt)Fe5O12garnet film composition grown earlier1by LPE on NdGaG substrates oriented (100) and (111) is now diluted (in steps) to 56 mol% of a hypothetical La1.35Lu1.7Fe5O12garnet. Most of the results reported are for films grown at 830 °C, but the effects of changing growth temperature for the compositions with the largest La–Lu substitutions are also discussed. La–Lu substitutions in fluxed melts significantly decrease film growth rates, and La must be present in melts in amounts in excess of those desired in the final crystal film. Both Pb from the fluxed melt and Pt from the crucible via the melt are incorporated into films in minor quantities. The ratio of rare earths and Pb to Fe and Pt in films is greater than the stoichiometric 0.6. The films support bubbles in the 0.5&mgr;m diameter range and have characteristic lengthlvalues of 0.037 to 0.062&mgr;m. Saturation magnetization values are 1700 to 2000 g (×10−4T). Domain wall damping coefficients are reduced in proportion to the amount of Sm replaced. The g factor is about 2 for all the films. Thel, magnetic anisotropy Ku, and stability factor Q are decreased by La–Lu substitutions for (100) films, but they are first increased slightly then decreased for (111) films. With the largest La–Lu substitution, (100) films have zero Q. The highestl, Ku[3.6×105erg/cm3(×10−1J/m3)] and Q (2.5) exist for (100) films with no La.

ISSN:0021-8979    

DOI:10.1063/1.326777

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Films of (100) EuIG doped with Sb or Ca:Ti and (100) EuYIG doped with Sb were grown with various Pb contents from a PbO:5.5 B2O3(mole ratio) based flux. The large Pb‐induced uniaxial anisotropy, which occurs in (100) Pb:EuIG films was not reduced significantly by Sb or Ca:Ti additions. Thel‐parameter decreased from 0.07 for undoped films to about 0.04 to 0.05, for doped films at Pb contents between 0.6 and 0.8 moles/formula unit. These data suggest that Sb and Ti had substituted for the octahedral Fe and had increased the magnetization. The Q‐factor for films with thesel‐parameters was about 2. It is further assumed that Pb is incorporated as Pb2+and Pb4+on different cation sites according to the model of Scott and Page. A comparison of our calculated and measured values of &Dgr;a support this model.

ISSN:0021-8979    

DOI:10.1063/1.326778

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Thulium has been substituted for yttrium in melts for the growth of (Y,Sm,Lu,Ca)3(Fe,Ge)5O12epitaxial garnet films for the purpose of reducing the magnitude of the temperature coefficient &agr;bcof the bubble collapse field. As an extension of previous substitutions [J. E. Davies, G. Galli, and J. C. Suits, J. Appl. Phys. 49, 1859 (1978)] of Tm for Lu to smaller bubble diameters, growth conditions were adjusted to produce films of nearly identical thickness (1.40 &mgr;m) and characteristic length (0.222 &mgr;m at 25°C) for Tm substitutions up to 0.25 atoms in the formula unit. This substitution was found to decrease the magnitude of &agr;bcas measured at 50°C by approximately 0.04%/°C⋅Tm atom. Anisotropy remains nearly constant with Tm substitution.

ISSN:0021-8979    

DOI:10.1063/1.326779

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The growth characteristics and the magnetic properties of Mn‐substituted garnet films grown on (110) oriented substrates are reported. On perfectly oriented substrates hillocks are observed which occur due to the fact that (110) is a habit face. By the introduction of a slight misorientation of the substrates, the hillocks disappear and the surfaces are perfectly flat. Mn is substituted in the garnet to obtain the right magneto‐elastic properties. It is shown that the temperature dependence of the magnetic parameters can be adjusted such as required to provide a device material.

ISSN:0021-8979    

DOI:10.1063/1.326780

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Composite structures consisting of YIG and (YSmLuCa)3(FeGe)5O12layers were prepared from two different fluxes. YIG was grown from a lithium and yttrium molybdate flux. (YSmLuCa)3(FeGe)5O12which supports 2.5 &mgr;m bubbles was grown from conventional lead borate flux. The very slow growth rates obtainable from molybdate flux makes it ideal for the deposition of submicron thick YIG layers. YIG grown from this flux was found to contain lithium. The lithium content appears to correlate with the observed magnetic and electrical properties. A technique for measuring submicron thick YIG films is described. The effects of YIG on hard bubble suppression in (YSmLuCa)3(FeGe)5O12is reported.

ISSN:0021-8979    

DOI:10.1063/1.326781

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A positive dependence of bubble domain coercive force on inverse film thickness has been attributed to coercivity associated with the film substrate interface [E. B. Moore, B. A. Calhoun, and K. Lee, J. Appl. Phys. 49, 1879 (1978)]. An alternate quantitative explanation is offered that is based on the distribution statistics of ions which possess large single ion magnetic anisotropy. It is shown that the measured coercive force vs film thickness when considered together with magnetic anisotropy provides an estimate of the growth induced order parameter. The order parameters so computed, based on the data reported by Moore, Calhoun, and Lee [ibid.] and Vella‐Coleiroetal. [G. P. Vella‐Coleiro, F. B. Hagedorn, S. L. Blank, and L. C. Luther, J. Appl. Phys. 50, 2176 (1979)] are on the order of 5% which compares favorably with spin resonance measurements performed on Nd3+in YAG [M. D. Sturge, S. L. Blank, and R. Wolfe, Mat. Res. Bull. 7, 989 (1972)]. It seems clear from this analysis that the proposed mechanism could be a major, if not dominant, source for the thickness dependence of coercive force.

ISSN:0021-8979    

DOI:10.1063/1.326782

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A series of Ca‐doped YIG films in which the atomic ratio of Ca to Y in the melt varied from 0 to 1.18 were grown. Resistivities of the virgin state of these films were measured. The dependence of the linewidth when the field is applied at 30° from the film normal on the Ca/Y atomic ratio was found to be linear and the dependence of the field isappliednormalto the film surface. These are clear indications of the eddy current damping mechanism. The linewidth contribution due to this mechanism is given by &Dgr;He.c.= (2&pgr;/c2&ggr;) &sgr;A&ohgr;2where &sgr; is the conductivity, A is the disc area, &ohgr; is the radial frequency and the magnetic field is applied normal to the film plane.

ISSN:0021-8979    

DOI:10.1063/1.326783

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Magnetic anisotropy was studied in a monocrystalline, epilayer of magnesium ferrite. This epilayer, 1.2 &mgr;m thick, was prepared by CVD on /100/ cleavage surfaces of MgO substrates at 1550 °K. Anisotropy measurements were performed by FMR and torque methods at room temperature. The parameters characterizing this epilayer are: 4&pgr;M=1650 G, K1=−3.2×104ergs/cc, Kn=1.2×105ergs/cc and a quality factor q=1.1.

ISSN:0021-8979    

DOI:10.1063/1.326784

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

In last decade years, we have payed attention to new bubble materials: monocrystalline epilayers and monocrystalline platelets of ferrites with spinel structure. In these materials cylindrical magnetic domains have been obtained. The perpendicular magnetic anisotropy occuring therein is a primary parameter, defining the properties of these bubble materials. The source of this anisotropy does not reside in the crystallographical structure of the materials, which are ferrimagnetics with cubic structure. The epilayers were obtained by CVD method on monocrystalline MgO substrates on the /100/ crystallographical surface in the 1100–1340 C temperature range. The dominant source of the perpendicular anisotropy observed in epilayer formed by CVD onto nonmagnetic substrates is magnetostriction. Can be summarized as follows: 1/ epilayers of ferrites are normally in a state of mechanical stress &sgr; due to mismatch between lattice constants. 2/ if the ferrite epilayer is magnetostrictive this stress produces a uniaxial magnetic anisotropy, 3/ with negative magnetostriction constants the easy axis is normal to the epilayer plane if this epilayer is in tension &sgr;≳0. The parameters characterizing the ferrite epilayers are: thickness 5 to 20 &mgr;m; 4&pgr;M=0.4 to 2 kGs; K1=104to 105ergs/cc; Kn=104to 105ergs/cc; collapse field Hcol=0.4 to 2 kOe; characteristic length 0.04 to 0.05 &mgr;m; bubble diameter 1 to 7 &mgr;m; bubble mobility, measured by FMR, is 40 to 250 cm/Oes and quality factorqabout 1.

ISSN:0021-8979    

DOI:10.1063/1.326785

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The discrimination of bubble states by dynamic bubble collapse was studied for 5 and 3 &mgr;m bubble films. We obtained bias field margin of 6 Oe for the 5 &mgr;m bubble film (S=1H and S=0), and about 10 Oe for 3 &mgr;m bubble films (S=1H and S= (120)). The discrimination was also tried for 3 &mgr;m bubble YY‐propagation pattern chips, for which we got about 8 Oe of bias field margin. Demonstrated was this collapse discrimination for ’’1111...’’ ’’0000...’’, and ’’1010...’’ bubble patterns utilizing an on‐chip bubble annihilator.

ISSN:0021-8979    

DOI:10.1063/1.326786

出版商:AIP    

年代:1979

数据来源: AIP