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The effect of volume fraction of B2-type ferromagnetic (FM) phase on magnetic behavior of melt-spun Fe52-xMn23+xGa25 (x=0, 1, 2, and 3) ribbons has been investigated. X-ray diffraction (XRD) results show that the volume fraction of the B2 phase is decreased, accompanied by the increased antiferromagnetic (AFM) fcc phase, with increasing x. The magnetization isotherms of these ribbons at different temperatures demonstrate that there exists a critical field HCR from AFM to FM state, and the HCR decreases and vanishes finally with increasing temperature. High exchange bias field (HEB) at 10K through a cooling field at HCR from 300K could be found and correlated to the volume fraction of B2-type FM phase. Both HCR and HEB are increased with decreasing the amount of B2-type FM phase. The HCR is increased from 20 kOe for x=0 to 50 kOe for x=3, and HEB is increased from 0.9 kOe for x=0 to 2.5 kOe for x=2. The latter phenomenon might be attributed to the change of exchange interactions at FM/AFM interfaces due to the change of proportion of FM and AFM phase at low temperature. [ABSTRACT FROM AUTHOR]

Mn60+xGa40-x (x=0, 5, 10, and 15) ribbons were prepared by the melt-spinning technique and subsequently by a heat treatment at 673K for 1 h. The magnetic phases Mn8Ga5, Mn1.86Ga, D019-Mn3Ga, and D022-Mn3Ga are found to appear in these annealed melt-spun ribbons. The Curie temperature TC of the ribbons varies from 125K to 185K as x changes from 0 to 5. For x=10, the hexagonal structure of the D019-Mn3Ga phase is distorted to an orthorhombic one below the phase transition temperature Td=185K. The optimized values for coercivity at room temperature are 0.13, 4.4, 8.1, and 7.7 kOe for the ribbons with x=0, 5, 10, and 15, respectively. The resistance measurements indicate that the ribbons show a typical metallic behavior for x=5-15. [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.

Structure, exchange interaction, magnetic properties and magnetostriction of a series of cubic C15 Mg[Cu.sub.2]-type rare-earth transition-metal (R-T) compounds of [Sm.sub.0.9][Pr.sub.0.1][([Fe.sub.1-x][Al.sub.x]).sub.2] (0 [is less than or equal to] x [is less than or equal to] 0.2) have been studied by x-ray diffraction, A. C. initial susceptibility, vibrating samples magnetometer and standard strain technology. The substitution of Al for Fe leads to an expansion of the lattice parameter a by 5.1%. Curie temperature [T.sub.c] is reduced continuously by replacing Fe with Al, which is ascribed to the decrease of the R-T coupling strength. The intersublattice coupling constant [J.sub.RT], molecular field coefficient [n.sub.RT], and exchange field [B.sup.ex], are evaluated by a molecular field model. The decrease of [J.sub.RT] with increasing Al content is related to the decrease of the number of (Sm, Pr)-Fe interacting pairs. Both the magnetostriction constant [[Lambda].sub.111] and the polycrystalline saturation magnetostriction [[Lambda].sub.s] at room temperature decrease with the Al addition, which can be ascribed to the decrease of the coupling strength. Index Terms--Exchange interaction, intersublattice coupling, magnetostriction, molecular field.

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.

The thermal stability, magnetocaloric effect, and refrigeration capacity (RC) of Gd-based Gd65Fe20Al15-xBx (x=0-7) glassy ribbons have been investigated. A relatively wide supercooled liquid region ΔTx(ΔTx=Tx-Tg) (50-80 K) and large reduced glass transition temperature Trg(Trg =Tg /Tm) (>0.63) are found in Gd65Fe20Al15-xBx glassy ribbons. The distinctive glass transition and sharp crystalline events as well as large values of ΔTx and Trg confirm the excellent glass forming ability of these alloys. The maximal magnetic entropy changes, -ΔSM max, and RC values of the specimens are about 4.80-5.21 J/kg K and 700-800 J/kg under 50 kOe, respectively. These -ΔSM max values are comparable to or even higher than that of some reported bulk metallic glasses. Moreover, the larger RC values are due to the broad ΔSM peak (∼200 K), which is caused by the glassy structure. The large ΔSM and RC values make the Gd-based Gd65Fe20Al15-xBx glassy ribbons attractive candidates for magnetic refrigeration materials. [ABSTRACT FROM AUTHOR]

Magnetic properties and microstructure of directly quenched Nd9.5Fe72.5-yTi2.5Zr0.5CryB15-xCx (x =0-1; y=0-3) magnets with a diameter of 1.1 mm and a length of 15 mm have been investigated. The thermomagnetic analysis show that the bulk magnets with x⩽0.5 and y=0-3 mainly consist of magnetically hard 2:14:1 phase. Besides, a slight substitution of C for B and Cr for Fe in Nd9.5Fe72.5-yTi2.5Zr0.5B15 can effectively refine the grain size of the bulk magnet with larger diameter, resulting in the remarkable enhancement of the magnetic properties. The optimal magnetic properties of Br=5.9 kG, iHc=8.2 kOe, and (BH)max=7.2 MGOe could be attained in Nd9.5Fe71.5-yTi2.5Zr0.5Cr1B14.5C0.5 magnet. [ABSTRACT FROM AUTHOR]

The crystal structure and magnetic properties of melt spun SmCo7-xMx (M=Ta, Cr, and Mo; x =0-0.6) ribbons have been investigated. Based on x-ray diffraction analysis, it is found that a pure TbCu7-type structure is formed in the melt spun SmCo7-xTax (x=0-0.3) ribbons, while minor amount of additional 2:17 phase appears for the SmCo7-xMx (M=Cr and Mo; x=0.1-0.6) ribbons, implying that the elements in VIB group (Cr and Mo) are inferior to the element in VB group (Ta) in stabilizing metastable 1:7 phase. The result, analyzed by Rietveld refinement method, shows that Ta, Cr, and Mo may occupy the 2e site of 1:7 phase, which leads to the enhancement of the magnetic anisotropy field of 1:7 phase, just like Ti, Zr, Hf, Nb, or V did. From the magnetic performance point of view, with increasing the content of doping element x from 0 to 0.6, the maximum coercivity of SmCo7-xMx ribbons is enhanced from 1.9 kOe for binary SmCo7 to 11.3 kOe for M=Ta, 6.6 kOe for M=Cr, and 7.5 kOe for M=Mo, respectively, while the remanent magnetization is all reduced for the above ternary alloy ribbons. [ABSTRACT FROM AUTHOR]

Magnetic properties, phase evolution, and microstructure of melt spun Sm(Co0.97M0.03)xCy (M =Hf and Zr; x=5-9; y=0-0.15) ribbons quenched at the wheel speed of 40 m/s have been investigated. X-ray diffraction analysis show that the main phases exist in Sm(Co0.97M0.03)x ribbons are 1:5 for x=5 and 5.5, 1:5 and 1:7 for x=6 and 6.5, 1:7 for x=7 and 7.5, 1:7 and 2:17 for x =8, and 2:17 for x=8.5 and 9. The grain size of 200-500 nm for these two series of ribbons is almost unchanged when x is increased from 5 to 9. Accordingly, the magnetic properties of Sm(Co0.97M0.03)x ribbons (M=Hf and Zr) are mainly dominated by their phase constitutions. Furthermore, a slight addition of C to Sm(Co0.97M0.03)x ribbons refines the grain size down to 10-50 nm, resulting in the improvement of magnetic properties. Sm(Co0.97Hf0.03)7.5C0.1 ribbons show the optimal magnetic properties of Br=6.9 kG, iHc=9.2 kOe, and (BH)max=10.0 MGOe. For the Sm-lean Sm(Co,Hf)xCy (x=8.5-9) ribbons, higher Hf and C content are required to improve the magnetic properties. The magnetic properties of Br=6.8 kG, iHc=6.2 kOe, and (BH)max =7.2 MGOe could be obtained in Sm(Co0.94Hf0.06)9C0.15 ribbons. [ABSTRACT FROM AUTHOR]

Single-phase epitaxial La0.47Ce0.20Ca0.33MnO3-δ films on (001) SrTiO3 were prepared by pulsed laser deposition and by reducing the oxygen pressure for deposition. The decrease in the magnitude of oxygen drives the transformation of Ce4+ to Ce3+ ion, restraining the appearance of CeO2 that usually exists as impurity in bulk La0.47Ce0.20Ca0.33MnO3. The magnetic transition temperature of the films increases with increasing the deposition oxygen pressure. The temperature dependence of the electrical resistance (R) of the single-phase films obeys the thermally activated behavior. A postannealing procedure was carried out on a film deposited in 0.4 Pa. The magnetic transition temperature is markedly increased and R is dramatically decreased by annealing. A metal-insulator transition occurs at 217 K with a magnetoresistance of -73% for the annealed film. This metal-insulator transition temperature is much higher than that of the bulk La0.47Ce0.20Ca0.33MnO3. [ABSTRACT FROM AUTHOR]

Unconventional exchange bias (EB) has been studied in CoCr2O4/Cr2O3 nanocomposites, in which the Curie temperature of the ferrimagnetic CoCr2O4 is much lower than the Néel temperature of the antiferromagnetic Cr2O3. A negative EB field of about 2.5 kOe at 5 K is achieved upon cooling in a field of 30 kOe. Meanwhile, the coercivity of the CoCr2O4 nanoparticles has been enhanced significantly by coupling with Cr2O3. The effect of the cooling field on the EB field and coercivity at 10 K has also been investigated. The domain-state model is used to interpret the unconventional EB. Cooling field may play a decisive role in the creation of the interfacial spin configuration for the unconventional EB, not only by exchange interaction between the induced magnetization of a polarized paramagnet and interfacial spins of an antiferromagnet but also by Zeeman interaction between the domain-state surplus magnetization and the external field. [ABSTRACT FROM AUTHOR]

We studied the effects of C substitution for B on structural and magnetic properties of Pr16Co76B8-xCx (0<=x<=8) alloys, prepared by mechanical alloying and subsequent annealing. An attempt to synthesize Pr2Co14C compound has been carried out by a gradual C substitution of B in Pr16Co76B8. The x-ray diffraction results show that after annealed at 1073 K for 30 min, Pr2Co14(B,C) phase with tetragonal Nd2Fe14B-type structure is formed as the main phase for 0<=x<=7. The Pr2Co14C phase has not been observed in mechanical alloyed B-free powders (x=8). The lattice parameter c of the Pr2Co14(B,C) phase decreases with increasing the carbon content. The highest coercivity of 21.9 kOe has been obtained in Pr16Co76B6C2 alloys. The spin-reorientation temperature TSR1 increases with increasing the carbon content from 663 K for x=0 to 685 K for x=7. However, the spin reorientation is observed at 40 K for Pr16Co76B6C2 and then the spin-reorientation temperature TSR2 is nearly unchanged at 125 K for Pr16Co76B8-xCx alloys with x=4, 6, and 7, which may be caused by the solubility of carbon atoms. The anomaly of the spin reorientation observed at low temperatures in C-substituted Pr16Co76B8-xCx (x=2, 4, 6, and 7) alloys may be related to the Pr3+ instability. [ABSTRACT FROM AUTHOR]

The effect of Co substitution on structure, phase transformation, and magnetic properties of R16Fe76-xCoxC8 (R≡Nd, Dy; 0<=x<=76) alloys prepared by a remilling process has been studied systematically. The process of remilling and subsequent annealing is more beneficial for the formation of Nd2(Fe,Co)14C compound in Nd16Fe76-xCoxC8 alloys than in Dy16Fe76-xCoxC8 alloys. The R2(Fe,Co)14C phase is obtained for Nd16Fe76-xCoxC8 alloys with 0<=x<=20 and Dy16Fe76-xCoxC8 alloys with 0<=x<=25. Higher Co content results in the formation of Nd2(Fe,Co)17Cδ-type phase and Dy(Fe,Co)7 phase for Nd16Fe76-xCoxC8 and Dy16Fe76-xCoxC8 alloys, respectively. The high coercivity, iHc=48.5 kOe, is achieved for Dy16Fe51Co25C8 alloy. [ABSTRACT FROM AUTHOR]

Dy1-xPrx(Fe0.35Co0.55B0.1)2 (0<=x<=1) Laves compounds with a cubic MgCu2-type structure were synthesized by arc melting and subsequent annealing. The lattice parameter of the Laves compounds linearly increases, while the Curie temperature TC decreases with increasing Pr content. The saturation magnetization Ms at 5 K or 295 K for the Dy1-xPrx(Fe0.35Co0.55B0.1)2 alloys decreases to reach a minimum, then increases with increasing Pr content. The composition for magnetic moment compensation is about x=0.55 at 295 K and x=0.65 at 5 K, respectively. The magnetostriction λ∥ or λ⊥ at room temperature was investigated either parallel or perpendicular to the applied field using a standard strain gauge technique. [ABSTRACT FROM AUTHOR]

The C15 Laves phase with composition Tb0.7Pr0.3(Fe0.9B0.1)1.93 has been synthesized by mechanical alloying and subsequent annealing process. The structure and magnetic properties of Tb0.7Pr0.3(Fe0.9B0.1)1.93 have been investigated. The effect of the annealing on the magnetic properties has been studied. The samples annealed at 773 K are found to have a coercivity of 6.66 kOe at room temperature. The coercivity decreases monotonically with increase in the annealing temperature. The epoxy/Tb0.7Pr0.3(Fe0.9B0.1)1.93 composites have been produced by a cold compression-molding technique. The magnetostriction of the epoxy/Tb0.7Pr0.3(Fe0.9B0.1)1.93 composites with different weight ratios of epoxy resin to powder is measured by a standard strain technique. The Tb0.7Pr0.3(Fe0.9B0.1)1.93 composites, with a weight ratio of epoxy resin to powder of 5:100, have a high magnetostriction of 810 ppm, at an applied magnetic field of 12 kOe. The Tb0.7Pr0.3(Fe0.9B0.1)1.93 alloy combines a high magnetostriction with a low coercivity, which is a promising magnetostrictive material. [ABSTRACT FROM AUTHOR]

The phase components, structures, and magnetic properties of Pr[SUB1-x]Gd[SUBx]Co[SUB5] (x = 0 - 1) powders synthesized by mechanical alloying and subsequent annealing have been investigated systematically. The optimal magnetic properties, with a coercivity of 12.5 kOe, a remanence ratio of 0.72, and a maximum energy product of 12.7 MGOe, have been obtained from PrCo[SUB5] powders milled for 5 h and annealed at 700°C for 2 min. The remanence and maximum energy product were decreased monotonically with increasing Gd content, whereas the coercivity was increased, reaching a maximum of 23.7 kOe in Pr[SUB0.2]Gd[SUB0.8]Co[SUB5] powders. X-ray diffraction and transmission electron microscopy observations reveal that an uniform (Pr,Gd) Co[SUB5]/(Pr,Gd)[SUB2]Co[SUB17] nanostructure with an average grain size of 20-30 nm forms in the powders annealing at 700°C. The obtained magnetic hardening apparently originates from the high anisotropy field of the hard (Pr,Gd)Co[SUB5] phase and the uniform nanostructure developed by mechanical alloying and subsequent annealing. [ABSTRACT FROM AUTHOR]

We have studied the nanocomposite magnets with nominal compositions of Nd[SUB8-x]Y[SUBx]Fe[SUB88]B[SUB4] (x = 0-4.0) by mechanical milling techniques and subsequent heat treatment. We find that there exists the beneficial effect of nonmagnetic Y substitution for magnetic Nd on magnetic properties in nanocomposite magnets. The extension of the exchange coupling length, due to a decrease of the anisotropy of the hard-magnetic phase, results in that more soft-magnetic grains participate well in the exchange coupling, improving the magnetic properties of the nanocomposite magnets. [ABSTRACT FROM AUTHOR]

Crystal structure, magnetic properties and magnetostriction of Dy[sub 0.7]Pr[sub 0.3](Fe[sub 1-χ] B[sub χ])[sub 2] (0 ≤ χ ≤0.20) have been investigated by means of x-ray diffraction, ac initial susceptibility, a vibrating sample magnetometer, and a standard strain technique. The matrix of Dy[sub 0.7]Pr[sub 0.3]Fe[sub 2] alloy consists of (Dy, Pr)Fe[sub 2] phase with a cubic MgCu[sub 2]-type structure and some amount of (Dy, Pr)Fe[sub 3] phase with a rhombohedral PuNi[sub 3]-type structure. The introduction of boron effectively restrains the emergence of the iron-rich phase and thus decreases the amount of (Dy, Pr)Fe[sub 3] phase. Dy[sub 0.7]Pr[sub 0.3](Fe[sub 1-χ]B[sub χ])[sub 2] alloy with χ = 0.05 contains small amount of (Dy, Pr)(Fe,B)[sub 3] phase, and those with χ = 0.10 and χ = 0.15 are essentially of a single (Dy, Pr)(Fe,B)[sub 2] phase. An unidentified minor phase appears when χ = 0.20. The lattice parameter of (Dy, Pr)(Fe,B)[sub 2] phase decreases monotonically with the boron substitution up to χ = 0.20, indicating that the boron atoms occupy the substitutional sites. The Curie temperature for (Dy, Pr)(Fe,B)[sub 2] phase obviously increases compared with the boron free one. The saturation magnetization at room temperature increases with increasing boron content for the alloys studied, suggesting that the partial boron substitution is beneficial to the increment of the exchange interactions in the Dy[sub 0.7]Pr[sub 0.3]Fe[sub 2] system. The increment of the magnetization originates from the decrement of iron content, because the Fe moment that aligns antiparallel with the Dy moment almost keeps constant in this system. Boron substitution for iron increases the lattice distortion and anisotropy, thus causes the decrease of the linear magnetostriction λ[sub a] = λsub ]-λ⊥ at the room temperature. [ABSTRACT FROM AUTHOR]

A large remanent strain has been normally observed in free-standing float zone-grown Tb[sub 0.3]Dy[sub 0.7]Fe[sub 2] (Terfenol-D) following the application of magnetic field or compressive stress. Such a strain is considered to be composed of two parts, leading to reversible and irreversible domain contributions to the magnetostriction, in which the irreversible part corresponds to the magnetostrictive jump effect belonging to non-180° domain wall motion, and the reversible part contributes to the slower changes of magnetostriction. With no stress applied, the specimen shows a jump field of 21 and 53 Oe for 180° and non-180° domain wall motion, respectively. The jump field, distribution width and hysteresis field for non-180° domain wall motion are all increased with increasing stress, indicating complicated interactions between magnetic domains and defects. Stacking faults are found by electron microscopy to often act as domain-wall pinning centers, and scanning probe microscopy shows specific domain configurations are formed around excess rare earth, twin boundaries, and grain boundaries due to induced stresses and demagnetization effects. The influence of such interactions on magnetostrictive performance is discussed. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The effects of a partial substitution of Cu or Nb for Fe on the structure and magnetic properties of mechanically alloyed Nd[sub 8]Fe[sub 84]Ti[sub 8] alloys were studied. Compared with Nd[sub 8]Fe[sub 84]Ti[sub 8] alloys prepared under the same conditions, the temperature necessary for the formation of the Nd(Fe, Ti)[sub 12] phase decreases from 900 to 750 °C with the addition of 3 at. % Cu. The addition of Cu hinders the nitrogenation of the Nd(Fe, Ti)[sub 12] phase. The pretreatment of hydrogenation on the Cu-added alloys at 300 °C facilitates the formation of nitrides. With increasing annealing temperature, the intrinsic coercivity of the nitrides increases until it attains a maximum at 850 °C. The addition of Nb is harmful to the formation of the perfect Nd(Fe, Ti)[sub 12] phase. For the 3 at. % Nb-containing alloys, annealing at 960 °C makes a metastable phase Nd(Fe, Ti)[sub 7] be formed. The addition of Nb is unfavorable for the intrinsic coercivity and the maximum magnetic energy product of the nitrides. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The effects of a partial substitution of Ga for Fe on the structure and magnetic properties of mechanically alloyed Nd[sub 8.4]Fe[sub 87.1]B[sub 4.5] were studied. With increasing Ga content, the magnetic properties of the nanocomposite magnets first improve, reach maxima at 1.1 at. % Ga, and then degrade. The addition of Ga helps to control the morphology, especially the grain sizes of both α-Fe and Nd[sub 2]Fe[sub 14]B. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Presents information on a study that examined the effects of annealing on the properties of magnetic granular CoCu alloy ribbons that were prepared by the melt-spun method. Research method; Results and discussion.

Presents a study that examined the structure and magnetic properties of neodymium-iron-titanium alloys and their nitrides. Methodology; Analysis of the magnetic coercivities of the samples; Examination of the dependence of the magnetic properties on the composition of the samples.

Focuses on a study on the effects of magnetoannealing on the giant magnetoresistance (GMR) in Fe[subx]Ag[100-x] granular films. Introduction to GMR effect in magnetic multilayers; Experimental procedures; Discussion on the change of GMR as a function of iron content in the as-sputtered silver-iron thin films.

The crystal structures and magnetic properties of the 40 nm brownmillerite SrMnO2.5 film, perovskite SrMnO3-δ film, and mixed-phase film have been systematically investigated. The features of the oxygen vacancy ordering superstructure in the brownmillerite SrMnO2.5 film are observed from HRSTEM as follows: the dark stripes with a periodicity of four (110) planes of the cubic perovskite appearing at an angle of 45° with the substrate-film interface and extra reflection spots in fast Fourier transformation patterns along the (001) plane. When annealing the brownmillerite SrMnO2.5 film under higher oxygen pressure, the top portion undergoes structure transition into perovskite SrMnO3-δ as seen in the mixed-phase film consisting of the perovskite SrMnO3-δ phase dominating at the top part and the brownmillerite SrMnO2.5 phase dominating at the bottom part. The magnetic properties and Mn valences of the brownmillerite SrMnO2.5 film indicate that this film, similar to the bulk, is antiferromagnetic with TN at 375 K. However, the strained tetragonal perovskite SrMnO3-δ film exhibits ferromagnetic behavior with Curie temperature at 75K and a saturation magnetization of 2.5μB/Mn at 2 K. Moreover, the top perovskite SrMnO3-δ phase of the mixed-phase film also exhibits ferromagnetic behavior evidenced by the existence of the exchange bias. We propose that the ferromagnetic properties in both the perovskite SrMnO3-δ film and the top perovskite SrMnO3-δ phase in the mixed-phase film originate from Mn3+-Mn4+ double exchange coupling. However, the formation of Mn3+ differs for the two samples in that it is caused by oxygen vacancies in the former and the distribution of oxygen content across the film during annealing in the latter. [ABSTRACT FROM AUTHOR]