RU2061112C1 - Epitaxial ferrite carnet structure - Google Patents

Abstract

FIELD: manufacture of small-size planar SHF instruments. SUBSTANCE: epitaxial ferrite garnet structure containing substrate made of gadolinium-gallium garnet of orientation (100) comprises ferrite-yitrium garnet film containing Ga, La and/or Se and disorientated from plane (100) to plane (110) through angle of α. The proposed structure allows for thermal stability of excitation frequencies of surface magnetostatic waves within temperature range of from -70 to +85 C. EFFECT: improved properties of the title structure. 1 cl, 2 dwg

Description

 The invention relates to single-crystal materials, in particular to epitaxial ferrite-garnet structures (EFGS) based on yttrium iron garnet (YIG), and can be used in the development and manufacture of small-sized planar microwave (microwave) devices on surface magnetostatic waves (PMSV).

≅ 5•10^-5oC^-1) в максимально широком интервале температур.To create planar microwave devices at PMSV, EFGSs are used, including an YIG-based epitaxial layer deposited on a gadolinium-gallium garnet substrate. One of the main requirements for PMSV devices is the stability of the PMSV excitation frequency when the ambient temperature changes. The temperature instability of the PMSV excitation frequency is mainly due to the temperature dependence of the saturation magnetization of the YIG epitaxial film. In this situation, it is of interest to find ways of thermal stabilization of the excited frequencies at a level sufficient for practical change (α _f =

≅ 5 • 10 ^-5o C ^-1 ) in the widest possible temperature range.

Closest to the invention in technical essence is an epitaxial ferrite-garnet structure (EFGS) containing an epitaxial film of a garnet garnet with the addition of Co ions and / or rare-earth metals obtained by liquid-phase epitaxy from a melt of the PbO B ₂ O _{3 system} on a single crystal substrate from non-magnetic garnet having a plane orientation of 100} Films of this type have an increased Faraday rotation angle and an anisotropy of the "easy plane" type, which allows them to be used to construct magneto-optics eskih valves waveguide type. The disadvantage of this structure is the increased value of the FMR line width, as a result of which it cannot be used in microwave information processing devices using magnetostatic waves.

 The purpose of the invention is the expansion of the temperature range of the temperature stability of the excitation frequencies of the PMSV.

The goal is achieved in that the epitaxial ferrite-garnet structure containing a substrate of HGG orientation (100) and an epitaxially deposited film based on yttrium iron garnet differs in that the latter is taken with a content of Ga, La and / or Sc, and the structure is disoriented from the plane (100) to the plane (110) at an angle of 0-15 ^about . The concentration of dopants Sc and La X 0-0.5 at / form. Ha at 0-1.6 at / form. which ensures low losses during the propagation of PMSV in the frequency range 1-10 GHz.

The temperature dependence of the PMSW excitation frequency in this structure has the form of a straight line with a temperature coefficient α _{f of} no more than 5 · 10 ^{-5 °} С ^-1 in a wide temperature range (-70) - (+ 185) ^о С. The effect is due to the fact that for the chosen orientation of the epitaxial layer, the change in the PMSV frequency from temperature caused by the instability of the saturation magnetization of the film is compensated by the equivalent and opposite change in frequency due to the temperature dependence of the demagnetizing factors of crystallographic anisotropy. Orientation dependence of the values of the demagnetizing factors leads to the fact that the misorientation angle δ ^of more than 15 increases the slope of the linear function f (T), and α _f becomes larger than 5 × 10 ^{-5 °} C ^-1.

The authors do not know the use of structures YIG (100) orientation to disorientation ^of 0-15 in other technical solutions.

Figure 1 shows the temperature dependence of the excitation frequency of PMSV in YIG films grown on GGG substrates:
position 1 sample 1, the orientation (100) ^of misorientation 0;
pos.2 sample 2, orientation (100), disorientation 5.2 ^o ;
pos.3 sample 3, the orientation (100) ^of misorientation 15;
pos. 4 sample 4, orientation (100), misorientation 16 ^about .

Figure 2 shows the temperature dependences of the excitation frequency of PMSV in doped YIG films grown on GGG substrates:
position 1 sample 5, the orientation (100) ^of misorientation 0;
4gM 585 G.
pos.2 sample 6, orientation (100), disorientation 5.2 ^o ;
4gM 446 G.
pos.3 sample 7, the orientation (100) ^of misorientation 15;
4gM 360 G
pos.4 sample 8, the orientation (100) ^of misorientation 16;
4gM 550 Gs
pos. 5 sample 9, orientation (110), misorientation 26.5 ^about
4gM 400 G.
EXAMPLE 1. Liquid phase epitaxy from a PbO-based melt solution was used to grow YIG epitaxial films on HGG substrates of (100) orientation with different misorientations of the (100) plane to the (110) plane, δ; sample 1, film thickness d 19.5 μm, 2 Δ H 0.6 Oe; δ 0 ^about ; sample 2, d 15 μm, 2Δ N 0.5 Oe; δ 5.2 ^o ; sample 3, d 21.2 microns; 2Δ N 0.7 Oe; δ = 15 ^about ; sample 4, d 17.9 μm, 2 ΔН 0.6 Oe, δ 16 ^about .

Samples 1, 2 and 3 had (α _f ) = 0, 1.5 · 10 ^-5 and 4.5 · 10 ^{-5 °} С ^-1, respectively, in the temperature range -80 - + 60С; sample 4 had a temperature coefficient (α _f ) = 5.5 · 10 ^{-5 °} C ^-1 .

PRI me R 2. The method of liquid-phase epitaxy from a solution-melt on the basis of PbO were grown epitaxial films of doped YIG with reduced saturation magnetization on substrates GGG orientation (100) with different misorientations δ sample 5, d 18.2 μm, 2Δ N 0.7 Oe 4gM 585 gauss, δ = ⁰ °;
sample 6, d 10,7 micron, 2Δ H 0.8 Oe 4gM = 446 gauss, δ 5,2 ^°;
sample 7, d 11,8 micron, 2Δ H 0.8 Oe 4gM = 360 gauss, δ 15 ^°;
sample 8, d 21 mm, 2 H Δ E 0.7, 4gM = 550 gauss, δ = 16 ^°;
sample 9, d 30 μm, 2 Δ Н 0.35 Oe, 4 gM = 400 G., δ 26.5 ^about (corresponds to the plane (210)).

Samples 5, 6 and 7 had (α _f ) ≅ 5 · 10 ^-5 in the temperature range from -60 to +20 ^о С, samples 8 and 9 had (α _f ) 8.5 · 10 ^{-5 о} С ^-1 . Thus, in the films grown on (100) orientation with a misorientation ^of δ = 0-15, the temperature coefficient (α _f) less than 5 × 10 ^{-5 °} C ^-1 in a wide temperature range. The increase (α _f ) at δ≥ 15 ^о is associated with an increase in the slope of the temperature dependence of the excitation temperature of the PMW.

The proposed structure allows for the thermal stability of the PMSV frequency at the level of (α _f ) ≃ 5 · 10 ^{-5 °} С ^-1 in a wide temperature range.

Claims (1)

Epitaxial ferrite-garnet structure containing a substrate of gadolinium-gallium garnet orientation (100) and an epitaxially deposited film based on iron-yttrium garnet, characterized in that the latter is taken with the content of Ca, La and / or Se, and the structure is disoriented from plane (100) to plane (110) at an angle of 0 15 ^o .

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