New Low-Temperature Ferromagnets

Holden, A. N.; Matthias, B. T.; Anderson, Philip W.; Lewis, Howard B.

doi:10.1103/physrev.102.1463

Cited by 85 publications

(23 citation statements)

References 2 publications

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“…The magnetic properties of these compounds have been studied since the 1950s,174, 175 but more extensively over the last 15 years. In particular, CrV analogues of Prussian blue have high T c values, for example, T c =376 K for KV II [Cr III (CN) 6 ]176 and T c =375 K for K 0.058 V II/III [Cr III (CN) 6 ](SO 4 ) 0.058 ⋅0.93 H 2 O 177.…”

Section: Molecular Magnetsmentioning

confidence: 99%

Control of Magnetic Properties through External Stimuli

Sato¹,

Tao²,

Zhang³

2007

Angew Chem Int Ed

1,071

615

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The magnetic properties of many magnetic materials can be controlled by external stimuli. The principal focus here is on the thermal, photochemical, electrochemical, and chemical control of phase transitions that involve changes in magnetization. The molecular compounds described herein range from metal complexes, through pure organic compounds to composite materials. Most of the Review is devoted to the properties of valence-tautomeric compounds, molecular magnets, and spin-crossover complexes, which could find future application in memory devices or optical switches.

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Section: Molecular Magnetsmentioning

confidence: 99%

Control of Magnetic Properties through External Stimuli

Sato¹,

Tao²,

Zhang³

2007

Angew Chem Int Ed

1,071

615

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“…[172,173] Die magnetischen Eigenschaften der Preußischblau-Analoga wurden seit den 50er Jahren untersucht, [174,175] doch hat das Interesse innerhalb der letzten 15 Jahre stark zugenommen. Eine hohe Leitfähigkeit zeigt dagegen ein erst kürzlich beschriebener organischer Halbleiter, der ein neutrales Spirobiphenalenyl-Radikal enthält.…”

Section: Magnetische Optische Und Elektronische Bistabilität In Eineunclassified

“…[161] Kürzlich wurde eine zweistufige Phasenumwandlung des Cyan-funktionalisierten Benzodithiazolylradikals (CBDTA) beschrieben. [ [167,168] [169,170] Die magnetischen Eigenschaften der Preußischblau-Analoga wurden seit den 50er Jahren untersucht, [174,175] doch hat das Interesse innerhalb der letzten 15 Jahre stark zugenommen. Besonders hohe Werte von T c zeigen CrV-Analoga, wie K[V II Cr III (CN) 6 ] mit T c = 376 K [176] und K 0.058 [V II/III -Cr III (CN) 6 ](SO 4 ) 0.058 ·0.93 H 2 O mit T c = 375 K. [177] Die Entdeckung von Magneten mit hohen T c -Werten hat intensive Studien der magnetischen Eigenschaften von Preußischblau-Analoga ausgelöst.…”

Section: Wechselwirkungen Als Auch Eine Domino-artige Rotation Derunclassified

Magnetische Molekülverbindungen: Schaltung magnetischer Eigenschaften durch externe Stimuli

2007

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Man kennt eine Vielzahl magnetischer Materialien, deren magnetische Eigenschaften durch externe Stimuli geschaltet werden können. Das Hauptaugenmerk liegt auf der thermischen, photochemischen, elektrochemischen und chemischen Steuerung von Phasenübergängen, die mit einem Wechsel der Magnetisierung einhergehen. Die Bandbreite der beschriebenen Spezies reicht von Metallkomplexen über rein organische Verbindungen bis zu Kompositmaterialien, wobei der Schwerpunkt dieses Aufsatzes auf den Eigenschaften von valenztautomeren Verbindungen, molekularen Magneten und Spin‐Crossover‐Komplexen liegt, für die Anwendungen als Speichermedien oder optische Schalter in Aussicht stehen.

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“…The alkali ions which maintain charge neutrality occupy cubic interstitial sites (not shown). 1 This chemical formula is a commonly used approximation though [8,9,12]. These compounds have the sodium chloride structure, with Co and Fe ions located on the vertices of a cubic lattice, each octahedrally coordinated by six cyano moieties (Fig.…”

Section: Figmentioning

confidence: 99%

“…Prussian Blue (PB) (Fe 4 [Fe(CN) 6 ] 3 ) is a long-known dye and prototypical transition metal co-ordination compound that exhibits ferro-magnetism [1,2,3] driven by superexchange coupling between iron spins. It is an important case of exchange coupling mediated through the CN − bridge [4].…”

Section: A Introductionmentioning

confidence: 99%

Muon spin relaxation study of the magnetism in unilluminated Prussian Blue analogue photomagnets

et al. 2006

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We present longitudinal field muon spin relaxation (µSR) measurements in the unilluminated state of the photo-sensitive molecular magnetic Co-Fe Prussian blue analogues M1−2xCo1+x[Fe(CN)6]·zH2O, where M=K and Rb with x = 0.4 and ≃ 0.17, respectively. These results are compared to those obtained in the x = 0.5 stoichiometric limit, Co1.5[Fe(CN)6]·6 H2O, which is not photo-sensitive. We find evidence for correlation between the range of magnetic ordering and the value of x in the unilluminated state which can be explained using a site percolation model. A. IntroductionPrussian Blue (PB) (Fe 4 [Fe(CN) 6 ] 3 ) is a long-known dye and prototypical transition metal co-ordination compound that exhibits ferro-magnetism [1,2,3] driven by superexchange coupling between iron spins. It is an important case of exchange coupling mediated through the CN − bridge [4]. Much of the recent interest in magnetic compounds related to PB (including a few that have been studied with µSR [5,6,7]) is motivated by potential novel behavior and related applications in molecular magnetism [8,9], including magnetism that is sensitive to exposure to light, i.e. photomagnetism.The compounds studied in this paper are the molecule based Co-Fe PB analogues (Co-Fe PBAs)1: (Color online) Crystal structure of M1−2xCo1+x[Fe(CN)6]·zH2O: (a) x = 0.5; (b) x = 0.5, with an Fe(CN)6 vacancy shown in gray coordinated by bound water molecules. Large, medium and small circles denote Fe, Co, and CN, respectively. The alkali ions which maintain charge neutrality occupy cubic interstitial sites (not shown).1 This chemical formula is a commonly used approximation though [8,9,12]. These compounds have the sodium chloride structure, with Co and Fe ions located on the vertices of a cubic lattice, each octahedrally coordinated by six cyano moieties (Fig. 1). The Co and Fe ions are connected via cyanide bridges with interstitial alkali metal ions and water molecules [9,13] (Fig. 1(b)). Co-Fe PBAs are in general non-stoichiometric and significant structural disorder (vacancies in the Fe(CN) 6 sites) is present. Depending on the stoichiometry and synthesis route, the materials are paramagnets or exhibit magnetic ordering at temperatures below ∼ 25 K, due to small superexchange coupling J between Fe III and Co II moments.Illumination of Co-Fe PBAs with broadband visible light in the range of ∼ 550 − 750 nm can cause dramatic changes in the magnetic properties, including an increase in magnetization and ordering temperature. The proposed origin of the photomagnetic effect is a light-induced charge transfer from the state: Fe II (t 6 2g , S = 0)-CNCo III (t 6 2g , S = 0) to the meta-stable self-trapped state: Fe III (t 5 2g , S = 1/2)-CN-Co II (t 5 2g e 2 g , S = 3/2) [9,14], effectively increasing the concentration of magnetic moments. The non-stoichiometry is believed essential for the photoinduced magnetization [14]. However, in spite of considerable experimental and theoretical effort, the microscopic mechanism of the photomagnetic effect and the nature of magnetic orde...

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New Low-Temperature Ferromagnets

Cited by 85 publications

References 2 publications

Control of Magnetic Properties through External Stimuli

Control of Magnetic Properties through External Stimuli

Magnetische Molekülverbindungen: Schaltung magnetischer Eigenschaften durch externe Stimuli

Muon spin relaxation study of the magnetism in unilluminated Prussian Blue analogue photomagnets

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