Results 1 - 10 of 2855
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[en] Highlights: • We developed Alnico 8 alloys with excellent properties (a(RT-180 °C) = −1.25 %%/°C). • The three-step aging optimizes the dispersed distribution of the a1 phase. • The three-step aging makes the a1 phase be single domain particles. • The three-step aging improves the thermal stability of Alnico alloys. - Abstract: The correlations of phase structure and thermal stability for Alnico 8 alloys is analyzed by three-step aging at 650 °C, 600 °C and 550 °C gradually in this paper. After three-step aging the a1 phase is a chess-like structure in transverse direction and a bamboo-like structure in longitudinal direction. Meanwhile the magnetic energy product ((BH)m) increases from 9.17 MGOe to 10.59 MGOe, and the remanence temperature coefficient a(RT-180 °C) reduces from −2.31 %%/°C to −1.25 %%/°C. The MPMS and VSM measurements indicate that three-step aging makes the a1 phase be single domain particles and dispersed distribution, which plays an important role in optimizing the thermal stability of Alnico alloys.
[en] Two highly sensitive magnetometers: resonance-vibrating sample magnetometer and magneto-optical Kerr effect for hysteresis loop measurements of nanostructures are described. They are simple from the electronic point of view as well as from mechanical construction, the cost of designed instruments is very low in relation to commercial devices. The example measurement of minor hysteresis loops of MTJ is discussed
[en] This contribution reports for the 1st time on the magnetic behavior of CO_3O_4 nanoparticles synthesized by a “green” process using an Aspalathus linearis’ leaves natural extract. More accurately magnetic behavior of CO_3O_4 nanoparticles successfully biosynthesized was investigated using vibrating sample magnetometer. The magnetization behavior for the samples manifests a combination of size dependent antiferromagnetic and paramagnetic behaviors, respectively, for the core and shell of the nanoparticles. - Highlights: • 1"s"t report on magnetic behavior of Co3O4 nanoparticles via Aspalathus linearis. • Co_3O_4 nanoparticles manifest size-dependent antiferromagnetic & paramagnetic behaviors. • Antiferromagnetic & paramagnetic behaviors were confirmed by VSM.
[en] In a vibrating sample magnetometer the signal contains a spurious component due to the ac magnetization induced in the sample as it vibrates in an imperfectly uniform dc magnetic field. In high-conductivity and superconducting samples, the spurious signal may be larger than that due to the dc magnetization. A quantitative analysis is given, and measurements made in an uncompensated solenoid are compared with those made in a fourth-order solenoid
[en] In industrial application, the magnetic properties of the magnetic composites do not have to be too high In China. the omset of composite bascd on hcxafcrritc (US S 52 million) is higer than thc compositc based on NdFeB (US S 13.5 million The use of polymcr as binder in magnctic compositcs gives matcrials with cxccllcnt properties such as light, flexible and cheap Thc elasticity of the magnetic composites depends on the properties of the polymer matrix used in the materials. When hexafemtc powder is binded with an elastic polymer. elastoferrite is obtained In this study, hexaferrite SrO.6Fe2O3 (SrM) and BaO.6Fe2O3 (BaM) which was calsinated at 1200o was used with EV A/ETP as binder These two materials were mixed in Labo Palstomill at 130oC for 7 minutcs with rotation speed of 30 rpm The volume fraction of the hexafcmtc powder was varrlcd (30. 40 and 50%). The mixture was pressed to obtaIn sheets. The sheets were characterization to obtain: mechanical, magnetlcal and microstructure properties. The particle size and shape of SrM and BaM podwer were measured with SEM. The particle size of SrM and BaM are 1.6 um and I.2 um respectively The SrM shape is flaky and the BaM shape is nodular Mechanical properties of the composite based on EVA is better than that based on ETP At 30% volume faction. the tensile strength of EVA composite is 44.(,8 kg/cm3 while the ETP composite is 19.72 kg/cm3 The magnetic properties of both composites (EVA and ETP) were charactcrized. The result show that for EVA composites, the lowest energy value was 0.0400 MGOe (30% BaM volume fractIon) and the highest energy value was 0.21860 MGOe (50% SrM volume fraction). For ETP composites, the lowest energy value 0.0242 MGOe (30% SrM volume fractIon) and the hghest energy value was 02262 MGOe (40% BaM volume fraction)
[en] Octahedral-like CoFe2O4 ferrite was fabricated using an ethylenediaminetetraacetic acid (EDTA)-assisted route under mild conditions. EDTA plays important roles in the formation of the products in the process. Also, the magnetic properties of the samples were characterized on a vibrating sample magnetometer (VSM)
[en] A vibrating-sample magnetometer has been designed and constructed to permit magnetization investigations of condensed matter in fields up to 6.0 T over a temperature interval from approx. 80 to 800 K. The primary motivation for this construction was to provide an overlap capability with an existing low-temperature vibrating-sample magnetometer (LTVSM) for investigations of the normal-state magnetic properties of A15 superconductors well above the superconducting transition temperature. At these higher temperatures, the inherently larger heat capacities and the decrease in sensitivity of cryogenic thermometers result in diminished performance of the LTVSM
[en] In this article the magnetic micron-sized carbonyl iron (CI) microbeads have been prepared using alginate-gelatin (Al-Ge) as a wrapping agent for the first time. The sodium alginate (Na-Al) and gelatin components were cross-linked by Ca2+ and genipin to produce an interpenetrating network, respectively. The Al-Ge network can restrict the oxidation of CI particles and hence contribute to higher dispersion stability and magnetic properties for the core–shell structured Al-Ge-CI microbeads. In a series of experiments, we compared different gelatin concentrations for the encapsulation in order to optimize the flexibility and stability of microbeads. It is important to mention that the resulting magnetic Al-Ge-CI microbead is stable and dispersed throughout the complete synthesis process, which is a promising magnetic Al-based material. And the influence of the coating layers on the magnetic properties was examined by a vibrating sample magnetometer. Furthermore, the effects of predetermined time on swelling and water retention behaviours for the magnetic microbeads were illustrated. (paper)
[en] Although magnetic accommodation has been known for a long time, scalar accommodation has only recently been modeled. Vector accommodation observed in a rotating vibrating sample magnetometer has not been modeled. This paper presents the first model for vector accommodation