Structural and magnetic properties of Ni substituted M-type Ca-Sr hexaferrites synthesized by solid-state reactions

Yujie Yang 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.5

In this study, we have prepared the M-type Ca-Sr hexaferrites with composition of Ca0.2Sr0.8Fe12.0-xNixO19 (0.0 ≤ x ≤ 0.8) by thesolid-state reactions. The phase compositions of the samples were confirmed by X-ray diffraction analysis. The results of Xraydiffraction patterns show that for the M-type hexaferrite magnetic powders with the Ni content (x) from 0.0 to 0.4, theXRD patterns belong to the M-type strontium hexaferrite; when Ni content (x) ≥ 0.6, Sr4Fe6O13 is detected. It is observed thatlattice parameter c first increases with the increase of Ni content (x) from 0 to 0.4, and then decreases when Ni content (x) ≥0.4, while lattice parameter a basically keeps constant. Magnetization properties were measured at room temperature by apermanent magnetic measuring system. The remanence (Br) first increases with increasing Ni content (x) from 0.0 to 0.2, andthen decreases when Ni content (x) ≥ 0.2. The the intrinsic coercivity (Hcj), magnetic induction coercivity (Hcb) and maximumenergy product [(BH)max] decrease with the increase of Ni content (x) from 0.0 to 0.8.

On Alleviation of New User Problem in Collaborative Filtering using SNA Theory

Yang Yujie,Zhang Huizhi,Wang Xianfang 보안공학연구지원센터(IJUNESST) 2013 International Journal of u- and e- Service, Scienc Vol.6 No.6

Effect of Al doping on the magnetic properties of Sr0.1Ca0.6La0.3AlxFe12-xO19 hexaferrite magnets

Yujie Yang 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.7

Al substituted M-type hexaferrite samples, Sr0.1Ca0.6La0.3AlxFe12-xO19 (0 ≤ x ≤ 1.4), were synthesized by the ceramic process. The X-ray diffraction (XRD) was used to examine the phase composition of the magnetic powders. The XRD patterns of themagnetic powders at Al content (x) ≤ 0.8 show the M-type strontium hexaferrite phase with α-Fe2O3 as a second phase. At Alcontent (x) ≥ 1.0, there are single magnetoplumbite phase patterns. The images of the M-type hexaferrite magnets wereobserved by a field emission scanning electron microscopy (FE-SEM). The grain particles of the magnets are hexagonalplatelet-like shape, and the grain size decreases with the increase of Al concentration (x). A permanent magnetic measuringsystem was used to measure the magnetic properties of the magnets. The remanence (Br) decreases with Al content (x) from0 to 1.4. The intrinsic coercivity (Hcj) increases with Al content (x) from 0 to 1.4. While the magnetic induction coercivity (Hcb)first increases with Al content (x) from 0 to 0.6 and then decreases at Al content (x) ≥ 0.6.

The role of La content on microstructure and magnetic characteristics of the Sr1-x LaxFe11.80Cu0.20O19 hexagonal ferrites

Yujie Yang,Fanhou Wang,Juxiang Shao,Qilong Cao 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.6

Hexagonal ferrites Sr1-xLaxFe11.80Cu0.20O19 magnetic powders and magnets were prepared by the solid state reaction. The phasecompositions of the magnetic powders were identified by X-ray diffraction. There is a single magnetoplumbite phase in themagnetic powders with x from 0.12 to 0.32, and for the magnetic powders with x ≥ 0.36, the LaFeO3 phase is observed. Themicrostructures of the magnets were investigated by a field emission scanning electron microscopy. The magnets are formedof hexagonal-shaped crystals and the particles are distributed homogeneously. The magnetic properties of the magnets weremeasured by a magnetic properties test instrument. The remanence of the magnets increases with x from 0.12 to 0.40. However,the intrinsic coercivity, magnetic induction coercivity and maximum energy product of the magnets first increase with x from0.12 to 0.24, and then begin to decrease when x continues to increase.

Effect of LaPr-Co co-substitution on microstructure and magnetic properties for Ca0.4Sr0.6-x(La0.8Pr0.2)xFe12-y CoyO19 hexaferrites

Yujie Yang 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.7

M-type hexaferrites with nominal composition of Ca0.4Sr0.6-x(La0.8Pr0.2)xFe12-yCoyO19 (0.00 ≤ x ≤ 0.50, 0.00 ≤ y ≤ 0.40) wereprepared by the solid-state reaction method. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM)and a permanent magnetic measuring system were used to investigate the microstructural and magnetic properties of the Mtypehexaferrites. All the LaPr-Co substituted M-type hexaferrites are in single-phase with hexagonal structure and noimpurity phase is observed in the structure. The FE-SEM images of the magnets show that the grains are hexagonal plateletlike,and the grain size of the magnets basically keeps unchanged with increasing LaPr-Co content. The remanence (Br), firstdecreases, and reaches to the minimum value at x = 0.20, y = 0.16, and then increases with the increasing substitution contentof LaPr (0.20 ≤ x ≤ 0.50) and Co (0.16 ≤ y ≤ 0.40). The intrinsic coercivity (Hcj) increases with the increase of LaPr-Co content(0.00 ≤ x ≤ 0.40, 0.00 ≤ y ≤ 0.32), and then decreases with the increasing substitution content of LaPr (0.40 ≤ x ≤ 0.50) and Co(0.32 ≤ y ≤ 0.40). Magnetic induction coercivity (Hcb) and maximum energy product [(BH)max] increase with increasing LaPrCocontent (0.00 ≤ x ≤ 0.50, 0.00 ≤ y ≤ 0.40).

Effects of Pr-Co content on the microstructural and magnetic properties of the Pr-Co substituted M-type strontium hexaferrites

Yujie Yang 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.6

Pr-Co substituted M-type strontium hexaferrites with the chemical composition of Sr1-xPrxFe12-yCoyO19 (x = 0.00-0.50; y = 0.00-0.35) were prepared by the solid-state reaction method. Microstructures of the M-type hexaferrite samples were investigatedby the X-ray diffraction (XRD) and a field emission scanning electron microscopy (FE-SEM). The single-phase with hexagonalstructure is obtained in the M-type hexaferrites with Pr-Co content (0.00 ≤ x ≤ 0.20, 0.00 ≤ y ≤ 0.14). For the M-typehexaferrites with Pr-Co content (x ≥ 0.20, y ≥ 0.14), impurity phases are observed in the structure. The image of therepresentative magnet exhibits that the M-type hexagonal structure is formed in the magnet. A permanent magneticmeasuring system was used to measure the magnetic properties of the M-type hexaferrite magnets. The remanence (Br),maximum energy product [(BH)max] and Hk/Hcj ratios increase with the increasing substitution content of Pr (0.00 ≤ x ≤ 0.10)and Co (0.00 ≤ y ≤ 0.07), and then decrease with increasing substitution content of Pr (x ≥ 0.10) and Co (y ≥ 0.07). The intrinsiccoercivity (Hcj) and magnetic induction coercivity (Hcb) decrease with increaing Pr-Co content (0.00 ≤ x ≤ 0.30, 0.00 ≤ y ≤ 0.21),and then increase with increasing substitution content of Pr (x ≥ 0.30) and Co (y ≥ 0.21).

If No Trees, Where They Settle Down?

Yujie Yang 한국콘텐츠학회 2011 ICCC International Digital Design Invitation Exhib Vol.2011 No.5

Influence of Mn substitution on the magnetic and microstructural properties of the Sr0.75La0.25Fe12.00-x MnxO19 hexaferrites

Yujie Yang 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.2

A series of Mn substituted M-type hexaferrites having the chemical compositions of Sr0.75La0.25Fe12.00-xMnxO19 (where 0.00 ≤x ≤ 0.60) were prepared by the conventional ceramic processing method. X-ray diffraction (XRD) was used to evaluate thehexagonal phase evolution for the M-type hexaferrite magnetic powders. The XRD results show that Mn3+ ions completelyenter into the hexaferrite structure and all magnetic powders show M-type hexagonal structure. Magnetic properties of thepowders were studied by a physical property measurement system-vibrating sample magnetometer (PPMS-VSM). Thesaturation magnetization (Ms) and remanent magnetization (Mr) first slightly increase with Mn content (x) from 0.00 to 0.24,and then decrease with Mn content (x) form 0.24 to 0.60. The coercivity (Hc) of the magnetic powders first increases with Mncontent (x) from 0.00 to 0.12, and then decrease with Mn content (x) form 0.12 to 0.36, and increases with the increase of Mncontent (x) when Mn content (x) ≥ 0.36.

Impacts of heat treatment on the microstructure and magnetic properties of LaPr-Co substituted M-type CaSr hexaferrite

Yujie Yang 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.4

The M-type hexaferrite Ca0.4Sr0.3(La0.8Pr0.2)0.3Fe11.76Co0.24O19 was synthesized by the solid-state reaction method. The effects ofcalcination temperature and sintering temperature on the microstructural and magnetic properties have been carefullyinvestigated. The X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and a permanent magneticmeasuring system were used to investigate the microstructure and magnetic properties of the samples. Single-phase hexaferritepatterns are observed for the hexaferrite magnetic powders at different temperatures from 1210 to 1270 oC for 2 hrs. The FESEMimages of the magnets show that the hexagonal structures have been formed in the magnets, and the grains in themagnets are distributed evenly. With the increase of calcination temperature, the remanence (Br) and maximum energyproduct [(BH)max] increase from 1210 oC to 1270 oC, while the magnetic induction coercivity (Hcb) and intrinsic coercivity (Hcj)increase from 1210 oC to 1250 oC, and then decrease when the calcination temperature ≥ 1250 oC. With the increase ofsintering temperature, the remanence (Br) and maximum energy product [(BH)max] increase from 1180 to 1200 oC, while themagnetic induction coercivity (Hcb) and intrinsic coercivity (Hcj) increase from 1180 to 1195 oC, and then decrease when thecalcination temperature ≥ 1195 oC.

Microstructural and magnetic studies on the Cr substituted M-type CaSrLa hexaferrite magnets

Yujie Yang 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.3

A series of Cr substituted M-type hexaferrite Ca0.30Sr0.35La0.35CrxFe12-xO19 (0 ≤ x ≤ 1.05) magnets were prepared by theconventional solid state reaction method. The properties of the samples were characterized by X-ray diffraction (XRD), fieldemission scanning electron microscopy (FE-SEM) and a permanent magnetic measuring system. At Cr substitution (x) ≤ 0.60,XRD patterns of the magnetic powders show the M-type strontium hexaferrite phase with α-Fe2O3 as a second phase. WhenCr substitution (x) ≥ 0.60, there are magnetoplumbite phase patterns with only a small trace of α-Fe2O3 phase. The images ofthe magnets show that the hexagonal structures are formed, and the particle size keeps unchanged with increasing Crsubstitution (x). The remanence (Br) decreases with Cr substitution (x) from 0.00 to 1.05. The intrinsic coercivity (Hcj) increaseswith Cr substitution (x) from 0.00 to 1.05. While the magnetic induction coercivity (Hcb) first increases with Cr substitution(x) from 0 to 0.75 and then decreases at Cr substitution (x) ≥ 0.75.