Spin-polarised Electron Studies of Low-dimensional Magnetic Systems

Spin-polarised electrons provide unique experimental access to magnetic properties of surfaces and layered structures. The combined use of different techniques allows us to develop a microscopic picture of the physics underlying the macroscopic magnetic properties, e.g. magnetic phase transitions, magnetic coupling phenomena, exceptional surface magnetic properties. In this paper, two techniques are described together with the kind of questions addressed by them. Spin-resolved appearance potential spectroscopy gives local magnetic information about multi-component systems by probing the spin-dependent local density of unoccupied states. Spin-resolved inverse photo-emission measures specific electron states above the Fermi level. In particular, two-dimensional states serve as magnetic sensors at surfaces. Examples from surfaces as well as thin-film structures of band and local-moment ferromagnets are presented.

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Relationship between morphological and physical properties in nanostructured CuMnO2

10.3762/bxiv.2020.115.v1 ◽

2020 ◽

Author(s):

Hoa Thi Quynh Nguyen ◽

Hung Vinh Tran

Keyword(s):

Magnetic Properties ◽

Physical Properties ◽

Magnetic Phase ◽

Magnetic Phase Transitions ◽

Monoclinic Structure ◽

Strong Base ◽

Antiferromagnetic Ordering ◽

Divalent State ◽

Base Solution ◽

Low Dimensional

In this study, crednerite CuMnO2 nanostructures were prepared using a hydrothermal method at 100 °C with different amounts of NaOH mineralizator. Obtained nanostructured crednerite CuMnO2 with monoclinic structure (space group C2/m) exhibits two kinds of morphologies: nanobelts of the length of 1 - 1.5 µm and thickness of 15 - 25 nm, and nanoplatets being of 50 - 70 nm in diameter. Comparative studies of the preprepared samples reveal an intimate relationship between morphological and physical properties in nanostructured CuMnO2. A low NaOH concentration favours elongated crystal growth along the c-axis, creating nanobelt-shaped morphology. On the other hand, a strong base solution promotes the formation of nanoplates. Unique morphologies of nanostructured CuMnO2 affect distinct spectroscopic and magnetic properties. The nanobelt-shaped sample is characterized by the Raman active A1g mode at 637 cm-1 and a modified Curie-Weiss bahaviour. This phase exhibits two successive magnetic phase transitions: ferromagnetically at 9.2 K and antiferromagnetically at 42 K. Conversely, the nanoplate-shaped sample behaves typically as those reported in the literature, namely, the Raman active A1g mode at 688 cm-1 and low-dimensional magnetism with antiferromagnetic ordering below 62 K. The variation in the magnetic properties is presumably associated to the partial oxidation of Cu1+ and Mn2+ in the nanoplate-shaped sample compared to the divalent state of Cu2+ and trivalent Mn3+ ions in the nanobelt-shaped one.

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Periodic approach to the electronic structure and magnetic coupling in KCuF3, K2CuF4, and Sr2CuO2Cl2 low-dimensional magnetic systems

International Journal of Quantum Chemistry ◽

10.1002/qua.10862 ◽

2004 ◽

Vol 99 (5) ◽

pp. 805-823 ◽

Cited By ~ 32

Author(s):

Ib�rio de Pinho Ribeiro Moreira ◽

Roberto Dovesi

Keyword(s):

Electronic Structure ◽

Magnetic Coupling ◽

Magnetic Systems ◽

Low Dimensional

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Structural diversity and magnetic properties of six ferrocenyl monocarboxylate Mn(ii), Ni(ii) and Co(ii) complexes with 1D aqua, carboxyl or dinuclear hydroxyl bridges

CrystEngComm ◽

10.1039/d1ce00189b ◽

2021 ◽

Author(s):

Misbha Rafiq Khan ◽

Xiaoge Niu ◽

Tianling Chen ◽

Yan Liu ◽

Zhongyi Liu ◽

...

Keyword(s):

Magnetic Properties ◽

Magnetic Coupling ◽

Structural Diversity ◽

Different Types ◽

Structure Diversity

Six ferrocenyl monocarboxylate Mn(ii), Ni(ii) and Co(ii) complexes with different types of magnetic coupling bridges were synthesized successfully. 1–6 display intriguing structure diversity and magnetic properties.

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Exploring the magnetic properties and magnetic coupling in SrFe12O19/Co1-xZnxFe2O4 nanocomposites

Journal of Magnetism and Magnetic Materials ◽

10.1016/j.jmmm.2021.168095 ◽

2021 ◽

pp. 168095

Author(s):

P. Maltoni ◽

T. Sarkar ◽

G. Barucca ◽

G. Varvaro ◽

D. Peddis ◽

...

Keyword(s):

Magnetic Properties ◽

Magnetic Coupling

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Visualizing atomic structure and magnetism of 2D magnetic insulators via tunneling through graphene

Nature Communications ◽

10.1038/s41467-020-20376-w ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Zhizhan Qiu ◽

Matthew Holwill ◽

Thomas Olsen ◽

Pin Lyu ◽

Jing Li ◽

...

Keyword(s):

Magnetic Properties ◽

Deep Understanding ◽

Magnetic Coupling ◽

Atomic Scale ◽

Scanning Tunneling ◽

Tunneling Microscopy ◽

Electronic And Magnetic Properties ◽

Conducting Path ◽

Magnetic Insulators ◽

Quantum Technology

AbstractThe discovery of two-dimensional (2D) magnetism combined with van der Waals (vdW) heterostructure engineering offers unprecedented opportunities for creating artificial magnetic structures with non-trivial magnetic textures. Further progress hinges on deep understanding of electronic and magnetic properties of 2D magnets at the atomic scale. Although local electronic properties can be probed by scanning tunneling microscopy/spectroscopy (STM/STS), its application to investigate 2D magnetic insulators remains elusive due to absence of a conducting path and their extreme air sensitivity. Here we demonstrate that few-layer CrI3 (FL-CrI3) covered by graphene can be characterized electronically and magnetically via STM by exploiting the transparency of graphene to tunneling electrons. STS reveals electronic structures of FL-CrI3 including flat bands responsible for its magnetic state. AFM-to-FM transition of FL-CrI3 can be visualized through the magnetic field dependent moiré contrast in the dI/dV maps due to a change of the electronic hybridization between graphene and spin-polarised CrI3 bands with different interlayer magnetic coupling. Our findings provide a general route to probe atomic-scale electronic and magnetic properties of 2D magnetic insulators for future spintronics and quantum technology applications.

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Magnetic Properties of Embedded Rh Clusters in Ni Matrix

MRS Proceedings ◽

10.1557/proc-384-535 ◽

1995 ◽

Vol 384 ◽

Author(s):

Zhi-Qiang Li ◽

Yuichi Hashi ◽

Jing-Zhi Yu ◽

Kaoru Ohno ◽

Yoshiyuki Kawazoe

Keyword(s):

Magnetic Properties ◽

Electronic Structure ◽

First Principles ◽

Density Functional ◽

Local Density ◽

Magnetic Moments ◽

Functional Formalism ◽

Rhodium Clusters ◽

Spin Polarized ◽

Local Density Functional

ABSTRACTThe electronic structure and magnetic properties of rhodium clusters with sizes of 1 - 43 atoms embedded in the nickel host are studied by the first-principles spin-polarized calculations within the local density functional formalism. Single Rh atom in Ni matrix is found to have magnetic moment of 0.45μB. Rh13 and Rhl 9 clusters in Ni matrix have lower magnetic moments compared with the free ones. The most interesting finding is tha.t Rh43 cluster, which is bulk-like nonmagnetic in vacuum, becomes ferromagnetic when embedded in the nickel host.

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