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To investigate the reason for the reduction in damage resistance of InxGa1−xN with increasing indium (In) content, we used molecular dynamics methods to simulate the threshold displacement energies, the individual recoil damage and the overlapping cascade processes in InxGa1−xN (x = 0.3, 0.5, 0.7) during ion implantation. The average threshold displacement energy of InxGa1−xN decreases a little (from 41.0 eV to 34.6 eV) as the In content increases (from 0.3 to 0.7) and the number of defects produced by individual cascades increases less than 30% with increasing In content (from 0.3 to 0.7), while the overlapping cascade simulations showed that with In content increasing the dynamic annealing processes in cascades were significantly suppressed. Thus, the suppression of dynamic annealing in the cascades is the main reason for the reduction of damage resistance of InxGa1−xN by adding In content. The analysis of defect distribution during overlapping cascades showed that defects in In-rich InxGa1−xN (x = 0.7) agglomerate more rapidly as the irradiation dose increases and are likely to form large clusters, which are harder to anneal during cascade evolution. Therefore, the suppression of dynamic annealing in In-rich InxGa1−xN can be attributed to the rapid agglomeration of defects with the irradiation dose. [ABSTRACT FROM AUTHOR]

The structure, magnetic properties, and magnetostriction of Sm[sub 0.5]R[sub 0.5](Fe[sub 1-x]Co[sub x])[sub 2] compounds (R = Nd, Pr) have been investigated by using x-ray diffraction analysis, ac initial susceptibility, vibrating sample magnetometer, and standard strain techniques. It was found that the (Sm[sub 0.5]Nd[sub 0.5])Fe[sub 2] compound with MgCu[sub 2]-type cubic structure possesses low magnetocrystalline anisotropy and high ratio of magnetostriction to magnetocrystalline anisotropy. When Co is substituted for Fe, the Curie temperature of (Sm[sub 0.5]Nd[sub 0.5])(Fe[sub 1-x]Co[sub x])[sub 2] alloys exhibit a peak at x = 0.25 and the saturation magnetization increases with increasing Co content when x<0.25 and decreases when x≥0.5. The microstructure of (Sm[sub 0.5]Pr[sub 0.5])(Fe[sub 1-x]Co[sub x])[sub 2] alloys is nearly a single phase in the range of 0.75≤x≤1. The saturation magnetization and magnetostrictiom of the alloys exhibit a peak at x = 0.25 and x = 0.5, respectively. [ABSTRACT FROM AUTHOR]

Measurements of the structure, magnetic properties, and magnetostriction were made on arc-melted polycrystalline [([Tb.sub.0.7][Dy.sub.0.3]).sub.0.7][Pr.sub.0.3] [([Fe.sub.1-x][Co.sub.x].sub.1.85] (0 [is less than or equal to] x [is less than or equal to] 0.6) alloys by X-ray diffraction, initial susceptibility, vibrating sample magnetometry, and standard strain gauge techniques. The measurements showed that the matrix of [([Tb.sub.0.7][Dy.sub.0.3]).sub.0.7] [Pr.sub.0.3][(Fe.sub.1-x][Co.sub.x]).sub.1.85] predominantly consists of the Mg[Cu.sub.2]-type cubic Laves phase, with a small amount of Pu[Ni.sub.3]-type and rare-earth rich phases. The amount of (Tb, Dy, Pr)[(Fe, Co).sub.2] in [([Tb.sub.0.7][Dy.sub.0.3]).sub.0.7] [Pr.sub.0.3][([Fe.sub.1-x][Co.sub.x]).sub.1.85] increases with increasing Co concentration and becomes almost the only phase present when x [is greater than or equal to] 0.4. The lattice parameter decreases approximately linearly with increasing x from 0.7357 nm when x = 0 to 0.7300 nm when x = 0.6. The Curie temperature increases with increasing x from 640 K when x = 0 to 677 K when x = 0.3, and then decreases to 572 K when x = 0.6. The saturation magnetization [M.sub.s] exhibits a minimum near x = 0.3. The polycrystalline magnetostriction of [([Tb.sub.0.7][Dy.sub.0.3]).sub.0.7][Pr.sub.0.3] [([Fe.sub.1-x][Co.sub.x]).sub.1.85] decreases monotonically with increasing x. There is no evidence of an anomalously large [Lambda].sub.100] value as is the case for other R[([Fe.sub.1-x][Co.sub.x]).sub.2] compounds.

The magnetomechanical coupling coefficient, [k.sub.33], has been modeled as a function of the elastic modulus of the matrix, [E.sub.m], of composite magnetostrictive materials. Measurements of [k.sub.33] have been performed by a three-parameter technique on glass-matrix Terfenol-D composites fabricated from powders heated to 700 [degrees] C in an inert atmosphere under the application of a 1-3 kN force. It is concluded that there is a value of [E.sub.m] for optimum magnetomechanical performance which is dependent on the volume fraction, [V.sub.f]. The optimum value of [E.sub.m] is close to, but less than, the elastic modulus of the magnetostrictive material. Index Terms--Composite magnetostrictive materials, coupling coefficient, magnetostrictive, Terfenol-D.

The microstructure, magnetic properties and magnetostriction of [Tb.sub.0.2][Pr.sub.0.8][([Fe.sub.0.4][Co.sub.0.6]).sub.x] (1.65 [is less than or equal to] x [is less than or equal to] 1.90) alloys has been studied. The Curie temperatures for the 1:2 and 1:3 phases decrease with increasing x, whereas the saturation magnetization increases with increasing x. The remanent magnetization remains almost constant for all the samples and the coercivity decreases with increasing x. The spontaneous magnetostriction ([[Lambda].sub.111]) estimated from the splitting of the (440) lines is found to decrease with increasing x. The largest [[Lambda].sub.111] recorded for [Tb.sub.0.2][Pr.sub.0.8][([Fe.sub.0.4][Co.sub.0.6]).sub.1.65] is 2900 ppm at room temperature. Index Terms--Laves phase, microstructure, spontaneous magnetostriction.

Quasi-static and dynamic magnetomechanical measurements have been made on a twin-free oriented single crystal of [Tb.sub.0.27] [Dy.sub.0.73] [Fe.sub.2] (Terfenol-D). Unusually large values of dynamic strain coefficient, [d.sub.33], and magnetomechanical coupling coefficient, [k.sub.33], of 19.1 nm [A.sup.-1] and 0.83 respectively were recorded with an oscillating field of amplitude 500 A [m.sup.-1] rms at room temperature. The static magnetostriction saturated at 1688 x [10.sup.-6], however 90% of tiffs strain was achieved with a field of 45 kA [m.sup.-1]. The strain versus magnetization curves exhibit unusually linear regions, allowing confirmation that 71 [degrees] domain wall motion is primarily responsible for the high coupling coefficient of this material. Index Terms -- Magnetomechanical, inagnetostriction, single crystal, Terfenol-D

The structure, Curie temperature, and magnetostriction of SmZn1-xMnx polycrystalline crystals were investigated by x-ray diffraction, vibrating-sample magnetometer, and standard strain gauge techniques. It is found that SmZn1-xMnx alloys are nearly a single Sm(Zn,Mn) phase with the CsCl-type cubic structure up to x=0.2. The Curie temperature of SmZn1-xMnx alloys quickly increases with increasing Mn when x<=0.05 and gradually does in the range of 0.05

The magnetostriction and magnetization process of a twin-free Tb[SUB0.27]Dy[SUB0.73]Fe[SUB2] single crystal along the 〈110〉 direction has been studied by strain gauge, vibrating sample magnetometer, and domain observation techniques. It was observed that the magnetostriction of the sample remained unchanged with increasing magnetic fields when H < 1 kOe and quickly increased in the range 1 < H < 7.5 kOe. No "jump" effect was observed during the magnetization process and the magnetostrictive hysteresis was large when H < 2.5 kOe. Observations by the Bitter colloid technique at room temperature revealed curved domain walls which became straight at higher and lower temperatures in {100} and {111}, respectively, indicating the transition to different 180° walls for H<1 kOe. The domain patterns were clearest on a {100} surface. Above the spin reorientation temperature, 109° and 71° wall motions dominated the magnetization process in the range 1.5 kOe

Presents a study which investigated the structure, Curie temperature, and magnetostriction of alloys. Experimental procedure; Discussion on the properties of the alloy compounds; Results of the metallographic examination.

Provides information on a study that investigated the microstructure, Curie temperature and magnetorestriction of (Dy[sub0.65]Tb[sub0.25]Pr[sub0.1]) (Fe[sub1-x]Al[subx])[sub108] alloys. Experimental procedure; Results and discussion; Conclusion.