Impurity-Induced Spin-State Crossover in La0.8Sr0.2Co1−xAlxO3

We have prepared a set of polycrystalline samples of La 0.8 Sr 0.2 Co 1 − x Al x O 3 ( 0 ≤ x ≤ 0.2 ), and have measured the magnetization as functions of temperature and magnetic field. We find that the average spin number per Co ion ( S Co ) evaluated from the room-temperature susceptibility is around 1.2–1.3 and independent of x. However, we further find that S Co evaluated from the saturation magnetization at 2 K is around 0.3–0.7, and decreases dramatically with x. This naturally indicates that a significant fraction of the Co 3 + ions experience a spin-state crossover from the intermediate- to low-spin state with decreasing temperature in the Al-substituted samples. This spin-state crossover also explains the resistivity and the thermopower consistently. In particular, we find that the thermopower is anomalously enhanced by the Al substitution, which can be consistently explained in terms of an extended Heikes formula.

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Co-Substitution Effect in Room-Temperature Ferromagnetic Oxide Sr3.1Y0.9Co4O10.5

Materials ◽

10.3390/ma13102301 ◽

2020 ◽

Vol 13 (10) ◽

pp. 2301

Author(s):

Akihiro Tsuruta ◽

Shuji Kawasaki ◽

Masashi Mikami ◽

Yoshiaki Kinemuchi ◽

Yoshitake Masuda ◽

...

Keyword(s):

Magnetic Properties ◽

Saturation Magnetization ◽

High Spin ◽

Spin State ◽

Room Temperature ◽

High Spin State ◽

Substitution Effect ◽

Co Substitution ◽

Intermediate Spin ◽

Intermediate Spin State

We investigated the Co substitution effect for the magnetic properties in room-temperature ferromagnetic oxide Sr3.1Y0.9Co4O10.5. The substituted element (Al and Ga) and low-spin state Co3+, which was changed from a high-spin or intermediate-spin state by Al or Ga substitution, reduced the Curie temperature to even 1.5 times lower than the temperature estimated from a simple dilution effect. Al3+ preferentially substituted for intermediate-spin-state Co3+ in the ferrimagnetic CoO6 layer and deteriorated the saturation magnetization of Sr3.1Y0.9Co4O10.5. By contrast, Ga3+ substituted for high-spin-state Co3+ in the CoO6 layer and/or the antiferromagnetic CoO4.25 layer and enhanced the saturation magnetization per Co ion. These results indicate that the magnetic properties of Sr3.1Y0.9Co4O10.5 can be controlled by selectively substituting for Co3+ with different spin states.

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Transport And Magnetic Properties Of (Fe100-xVx)75 P15C10 Amorphous Alloys

Journal of Bangladesh Academy of Sciences ◽

10.3329/jbas.v35i2.9420 ◽

1970 ◽

Vol 35 (2) ◽

pp. 161-169

Author(s):

MAS Karal ◽

M Kamruzzaman ◽

FA Khan

Keyword(s):

Magnetic Field ◽

Magnetic Properties ◽

Saturation Magnetization ◽

Amorphous Alloys ◽

Melt Spinning ◽

Room Temperature ◽

Resistivity Measurement ◽

Anomalous Hall Effect ◽

Hall Resistivity ◽

Melt Spinning Technique

(Fe100-xVx)75 P15C10 (x = 0, 5, 10 and 15) amorphous alloys in the form of ribbon were prepared by the standard melt spinning technique and studied their transport and magnetic properties. The resistivity follows ‘Mooij correlation’ at low temperature (300 - 93) K. The Hall resistivity and the magnetoresistance (MR) were measured in an applied magnetic field up to 0.6T at room temperature (RT = 300 K). Anomalous Hall effect was observed in the Hall resistivity measurement and MR was found to vary 0 - 8%. The saturation magnetization gradually decreased with the increase of V in the alloys at RT. Key words: Resistivity; Mooij correlation; Hall resistivity; Magnetoresistance; Saturation magnetization DOI: http://dx.doi.org/10.3329/jbas.v35i2.9420 JBAS 2011; 35(2): 161-169

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ROOM TEMPERATURE SELF-ASSEMBLY GROWTH OF COBALT NANOWIRES UNDER MAGNETIC FIELDS

International Journal of Modern Physics B ◽

10.1142/s0217979205031602 ◽

2005 ◽

Vol 19 (15n17) ◽

pp. 2728-2733 ◽

Cited By ~ 1

Author(s):

YAOSHUN JIA ◽

QIANWANG CHEN ◽

MINGZAI WU

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Saturation Magnetization ◽

Hydrazine Hydrate ◽

Self Assembly ◽

Room Temperature ◽

Magnetic Measurements ◽

Average Diameter ◽

Cobalt Nanowires ◽

Growth Approach

Polycrystalline cobalt nanowires, with average diameter of 80 nm and length about 10 μm, were synthesized in the hydrazine hydrate solution at room temperature under magnetic fields. A seed-mediated growth approach was applied. Magnetic fields induced the growth of nanowires via aligned self-assembly of cobalt nanocrystallites. Magnetic measurements showed that the saturation magnetization (Ms) of the cobalt nanowires synthesized under magnetic field was five times larger than that of the samples prepared without magnetic fields; while the coercivity (Hc) of the sample prepared under magnetic fields was half of that of the sample synthesized without magnetic fields. The reasons for the magnetism changes were discussed.

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The Influence of the Soaking Process on Magnetization Saturation and Coercivity Field of the Classic Amorphous Alloy Fe61Co10Y8Nb1B20.

Revista de Chimie ◽

10.37358/rc.18.10.6632 ◽

2018 ◽

Vol 69 (10) ◽

pp. 2819-2822

Author(s):

Marcin Nabialek

Keyword(s):

Magnetic Field ◽

Saturation Magnetization ◽

Coercive Field ◽

Thermal Treatments ◽

Solid Samples ◽

Magnetization Saturation ◽

Transmission Geometry ◽

Negative Effect ◽

Coercivity Field ◽

The Magnetic Field

This study presents the results of Mossbauer research and magnetic properties. The tests were carried out for amorphous Fe61Co10Y8Nb1B20 alloys produced in the form of strips with a thickness of approximately 35 mm. Mossbauer spectra were measured in transmission geometry for solid samples. Measurements were taken for samples in solidified state and after two heating processes. The first process was carried out at 700K and 60 minutes, the second at 720K and 210 minutes. For the samples prepared in this way, magnetization tests were performed as a function of the magnetic field strength. The values of saturation magnetization and the value of the coercive field were determined from these matrices. It was found that the performed thermal treatments had a negative effect on the value of saturation magnetization and change in the value of the coercive field.

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The Structure and Magnetic Properties of NiZn-Ferrite Films Deposited by Magnetron Sputtering at Room Temperature

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.690-693.1702 ◽

2013 ◽

Vol 690-693 ◽

pp. 1702-1706 ◽

Cited By ~ 2

Author(s):

Shuang Jun Nie ◽

Hao Geng ◽

Jun Bao Wang ◽

Lai Sen Wang ◽

Zhen Wei Wang ◽

...

Keyword(s):

Thin Films ◽

Magnetic Properties ◽

Magnetron Sputtering ◽

Saturation Magnetization ◽

Room Temperature ◽

Oxygen Flow ◽

Flow Ratio ◽

Study Results ◽

Ferrite Thin Films ◽

Ferrite Films

NiZn-ferrite thin films were deposited onto silicon and glass substrates by radio frequency magnetron sputtering at room temperature. The effects of the relative oxygen flow ratio on the structure and magnetic properties of the thin films were investigated. The study results reveal that the films deposited under higher relative oxygen flow ratio show a better crystallinity. Static magnetic measurement results indicated that the saturation magnetization of the films was greatly affected by the crystallinity, grain dimension, and cation distribution in the NiZn-ferrite films. The NiZn-ferrite thin films with a maximum saturation magnetization of 151 emucm-3, which is about 40% of the bulk NiZn ferrite, was obtained under relative oxygen flow ratio of 60%.

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All organic multiferroic magnetoelectric complexes with strong interfacial spin-dipole interaction

npj Flexible Electronics ◽

10.1038/s41528-021-00120-0 ◽

2021 ◽

Vol 5 (1) ◽

Author(s):

Yuying Yang ◽

Zhiyan Chen ◽

Xiangqian Lu ◽

Xiaotao Hao ◽

Wei Qin

Keyword(s):

Magnetic Field ◽

Light Intensity ◽

Room Temperature ◽

Incident Light ◽

Dipole Interaction ◽

Interfacial Interaction ◽

Magnetoelectric Coupling ◽

Incident Light Intensity ◽

Organic Ferromagnets ◽

Magnetoelectric Coefficient

AbstractThe organic magnetoelectric complexes are beneficial for the development on flexible magnetoelectric devices in the future. In this work, we fabricated all organic multiferroic ferromagnetic/ferroelectric complexes to study magnetoelectric coupling at room temperature. Under the stimulus of external magnetic field, the localization of charge inside organic ferromagnets will be enhanced to affect spin–dipole interaction at organic multiferroic interfaces, where overall ferroelectric polarization is tuned to present an organic magnetoelectric coupling. Moreover, the magnetoelectric coupling of the organic ferromagnetic/ferroelectric complex is tightly dependent on incident light intensity. Decreasing light intensity, the dominated interfacial interaction will switch from spin–dipole to dipole–dipole interaction, which leads to the magnetoelectric coefficient changing from positive to negative in organic multiferroic magnetoelectric complexes.

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The nickel site in active Desulfovibrio baculatus [NiFeSe] hydrogenase is diamagnetic. Multifield saturation magnetization measurement of the spin state of Ni(II).

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)42527-6 ◽

1992 ◽

Vol 267 (11) ◽

pp. 7378-7380

Author(s):

C.P. Wang ◽

R Franco ◽

J.J. Moura ◽

I Moura ◽

E.P. Day

Keyword(s):

Saturation Magnetization ◽

Spin State ◽

Magnetization Measurement

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Review of Multi-Physics Modeling on the Active Magnetic Regenerative Refrigeration

Mathematical and Computational Applications ◽

10.3390/mca26020047 ◽

2021 ◽

Vol 26 (2) ◽

pp. 47

Author(s):

Julien Eustache ◽

Antony Plait ◽

Frédéric Dubas ◽

Raynal Glises

Keyword(s):

Magnetic Field ◽

Low Temperatures ◽

Room Temperature ◽

State Of The Art ◽

Vapor Compression ◽

Crucial Step ◽

Potential Alternative ◽

Vapor Compression Refrigeration ◽

Preliminary Study ◽

Physics Modeling

Compared to conventional vapor-compression refrigeration systems, magnetic refrigeration is a promising and potential alternative technology. The magnetocaloric effect (MCE) is used to produce heat and cold sources through a magnetocaloric material (MCM). The material is submitted to a magnetic field with active magnetic regenerative refrigeration (AMRR) cycles. Initially, this effect was widely used for cryogenic applications to achieve very low temperatures. However, this technology must be improved to replace vapor-compression devices operating around room temperature. Therefore, over the last 30 years, a lot of studies have been done to obtain more efficient devices. Thus, the modeling is a crucial step to perform a preliminary study and optimization. In this paper, after a large introduction on MCE research, a state-of-the-art of multi-physics modeling on the AMRR cycle modeling is made. To end this paper, a suggestion of innovative and advanced modeling solutions to study magnetocaloric regenerator is described.

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