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Fig. 5. (a) Curve showing the variation of Anisotropy Field (H,) with the number of Fe atoms substituted. (b) Plot showing the variation of anisotropy constant (K,) with the number of Fe atoms substituted. From this equation if HM,/M,, is plotted [81] as a function of M;,°, a straight line is obtained whose slope will be equal to 4K,/Mg and the point of intersection with the vertical axis is equal to 2K,/M,. The values of H,, K, and K> calculated by Eq. (1) are shown in Table 3. It was observed that the values of anisotropy fields calculated by both methods were nearly same. It was also observed that the value of anisotropy field increases after irradiation in unsubstituted as well as in Ga;Ingg substituted Sr- hexaferrite. Fig. 5(a) shows the variation of anisotropy field with the number of Fe atoms substituted. This increase in the value of H, in irradiated crystals may be explained to be due to appearance of new Fe** ions in

Figure 5 (a) Curve showing the variation of Anisotropy Field (H,) with the number of Fe atoms substituted. (b) Plot showing the variation of anisotropy constant (K,) with the number of Fe atoms substituted. From this equation if HM,/M,, is plotted [81] as a function of M;,°, a straight line is obtained whose slope will be equal to 4K,/Mg and the point of intersection with the vertical axis is equal to 2K,/M,. The values of H,, K, and K> calculated by Eq. (1) are shown in Table 3. It was observed that the values of anisotropy fields calculated by both methods were nearly same. It was also observed that the value of anisotropy field increases after irradiation in unsubstituted as well as in Ga;Ingg substituted Sr- hexaferrite. Fig. 5(a) shows the variation of anisotropy field with the number of Fe atoms substituted. This increase in the value of H, in irradiated crystals may be explained to be due to appearance of new Fe** ions in

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(a) Five iron sites, their spin direction, type, point symmetry, number of Fe ions per formula, and block situation in SrFe,,Oj9
(a) Five iron sites, their spin direction, type, point symmetry, number of Fe ions per formula, and block situation in SrFe,,Oj9
Fig. 1. M—H curve for the pristine unsubstituted and Ga-—In substituted Sr-hexaferrite. Fig. 1 shows the M-H curves for pure strontium hexaferrite and Ga-—In substituted ones. From Fig. | it is clear that the value of magnetization in case of pure SrFe,20j9 gets saturated at very low values of applied field i.e., less than 5 kOer but no saturation is observed in case of GasInog substituted strontium (Sr)-hexaferrite crystals. Since no saturation in magnetization is observed in Ga;Ino substituted Sr-hexaferrite even on application of the field upto 10kOer (the highest that we could achieve
Fig. 1. M—H curve for the pristine unsubstituted and Ga-—In substituted Sr-hexaferrite. Fig. 1 shows the M-H curves for pure strontium hexaferrite and Ga-—In substituted ones. From Fig. | it is clear that the value of magnetization in case of pure SrFe,20j9 gets saturated at very low values of applied field i.e., less than 5 kOer but no saturation is observed in case of GasInog substituted strontium (Sr)-hexaferrite crystals. Since no saturation in magnetization is observed in Ga;Ino substituted Sr-hexaferrite even on application of the field upto 10kOer (the highest that we could achieve
Mean electronic stopping power (S,), mean nuclear stopping power (S,), and mean projected range (R,) in pure and Ga-In substituted strontium hexaferrite at a fluence of | x 10'*ions/em? Table 2
Mean electronic stopping power (S,), mean nuclear stopping power (S,), and mean projected range (R,) in pure and Ga-In substituted strontium hexaferrite at a fluence of | x 10'*ions/em? Table 2
“Represents the values calculated by using Eq. (1). shows the calculated values of saturation magnetization, anisotropy field, Anisotropy constant and Curie temperature for both pristine and irradiated crystals
“Represents the values calculated by using Eq. (1). shows the calculated values of saturation magnetization, anisotropy field, Anisotropy constant and Curie temperature for both pristine and irradiated crystals
Fig. 2. Plot showing the M-H curves for pristine and 50 MeV Li** ion irradiated crystals of compositions: (a) SrFe;2O19; (b) SrGasIno,sFes.2019: (c) SrGa7In,.3Fe3 7019; and (d) SrGaoIn,; Fe2Oj9 along the c-axis. B. Kaur et al. / Journal of Magnetism and Magnetic Materials 305 (2006) 392-402
Fig. 2. Plot showing the M-H curves for pristine and 50 MeV Li** ion irradiated crystals of compositions: (a) SrFe;2O19; (b) SrGasIno,sFes.2019: (c) SrGa7In,.3Fe3 7019; and (d) SrGaoIn,; Fe2Oj9 along the c-axis. B. Kaur et al. / Journal of Magnetism and Magnetic Materials 305 (2006) 392-402
Fig. 3. A Plot showing comparison between the X-ray diffraction curves of unirradiated (UIR) and irradiated (IR) with 50MeV Li** ion beams SrFe,2Oj9 crystals. were insufficient to saturate the samples in the hard direction. Therefore, a straight-line extrapolation at higher fields was used to determine the intersection. Fig. 4(a shows the magnetization of the pristine unsubstituted SrFe;20j9 single crystals along and perpendicular to c-axis. As is clear from this figure that the magnetization gets saturated along c-axis at very low value of applied field bu does not get saturated even at 10kOer of applied field perpendicular to c-axis. So, here in this case, a straight-line extrapolation method is used to get the intersection poin of both curves 1.e, the value of Hy.
Fig. 3. A Plot showing comparison between the X-ray diffraction curves of unirradiated (UIR) and irradiated (IR) with 50MeV Li** ion beams SrFe,2Oj9 crystals. were insufficient to saturate the samples in the hard direction. Therefore, a straight-line extrapolation at higher fields was used to determine the intersection. Fig. 4(a shows the magnetization of the pristine unsubstituted SrFe;20j9 single crystals along and perpendicular to c-axis. As is clear from this figure that the magnetization gets saturated along c-axis at very low value of applied field bu does not get saturated even at 10kOer of applied field perpendicular to c-axis. So, here in this case, a straight-line extrapolation method is used to get the intersection poin of both curves 1.e, the value of Hy.
Fig. 4. (a) Graph showing the magnetization curves with applied field along and perpendicular to the c-axis in pristine SrFe;,Oj9. (b) Plot showing th M-H curve along and perpendicular to c—axis in case of SrGasIno.gFe¢.20 jo. The other method used to calculate the value of anisotropy field and anisotropy constants is described by Smit and Wijn [79]. The condition for K, = 0 applies if M-H curve in the hard direction is a straight line. In the event that the /—H curve does not turn out to be a straight
Fig. 4. (a) Graph showing the magnetization curves with applied field along and perpendicular to the c-axis in pristine SrFe;,Oj9. (b) Plot showing th M-H curve along and perpendicular to c—axis in case of SrGasIno.gFe¢.20 jo. The other method used to calculate the value of anisotropy field and anisotropy constants is described by Smit and Wijn [79]. The condition for K, = 0 applies if M-H curve in the hard direction is a straight line. In the event that the /—H curve does not turn out to be a straight
Fig. 6. M—T curves for Pristine and Li** ion irradiated: (a) SrFe,,»O,9 and (b) SrGasIng gFes »Oj9 crystals.
Fig. 6. M—T curves for Pristine and Li** ion irradiated: (a) SrFe,,»O,9 and (b) SrGasIng gFes »Oj9 crystals.
Fig. 7. Graph showing the variation of Curie temperature with the number of Fe atoms substituted.
Fig. 7. Graph showing the variation of Curie temperature with the number of Fe atoms substituted.
Related topics:
Mechanical EngineeringCondensed Matter PhysicsHeavy Ions PhysicsSwift Heavy Ion IrradiationCurie temperatureMagnetism and Magnetic Materials
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