High-Sensitivity Measurements of the Magnetic Properties of Materials at Cryogenic Temperatures

Великанов, Д. А.

doi:10.1134/s2075113320040413

Cited by 13 publications

(8 citation statements)

References 13 publications

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“…The low-temperature (4.2-20 K) magnetic susceptibilities of EuLnCuSe 3 (Ln = La, 0.050 g; Tb, 0.070 g; Dy, 0.090 g; Ho, 0.075 g; Y, 0.060 g; Tm, 0.155 g; Yb, 0.085 g and Lu, 0.055 g) were studied on a SQUID magnetometer (Kirensky Institute of Physics, Krasnoyarsk, Russia) [88,89] in a 10 Oe (796 A m −1 ) magnetic field. The measurements of low-temperature magnetization were performed in the zero-field cooled (ZFC) and nonzero-field cooled (FC) modes.…”

Section: Methodsmentioning

confidence: 99%

Quaternary Selenides EuLnCuSe3: Synthesis, Structures, Properties and In Silico Studies

Grigoriev

Solovyov

Русейкина

et al. 2022

IJMS

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In this work, we report on the synthesis, in-depth crystal structure studies as well as optical and magnetic properties of newly synthesized heterometallic quaternary selenides of the Eu+2Ln+3Cu+1Se3 composition. Crystal structures of the obtained compounds were refined by the derivative difference minimization (DDM) method from the powder X-ray diffraction data. The structures are found to belong to orthorhombic space groups Pnma (structure type Ba2MnS3 for EuLaCuSe3 and structure type Eu2CuS3 for EuLnCuSe3, where Ln = Sm, Gd, Tb, Dy, Ho and Y) and Cmcm (structure type KZrCuS3 for EuLnCuSe3, where Ln = Tm, Yb and Lu). Space groups Pnma and Cmcm were delimited based on the tolerance factor t’, and vibrational spectroscopy additionally confirmed the formation of three structural types. With a decrease in the ionic radius of Ln3+ in the reported structures, the distortion of the (LnCuSe3) layers decreases, and a gradual formation of the more symmetric structure occurs in the sequence Ba2MnS3 → Eu2CuS3 → KZrCuS3. According to magnetic studies, compounds EuLnCuSe3 (Ln = Tb, Dy, Ho and Tm) each exhibit ferrimagnetic properties with transition temperatures ranging from 4.7 to 6.3 K. A negative magnetization effect is observed for compound EuHoCuSe3 at temperatures below 4.8 K. The magnetic properties of the discussed selenides and isostructural sulfides were compared. The direct optical band gaps for EuLnCuSe3, subtracted from the corresponding diffuse reflectance spectra, were found to be 1.87–2.09 eV. Deviation between experimental and calculated band gaps is ascribed to lower d states of Eu2+ in the crystal field of EuLnCuSe3, while anomalous narrowing of the band gap of EuYbCuSe3 is explained by the low-lying charge-transfer state. Ab initio calculations of the crystal structures, elastic properties and phonon spectra of the reported compounds were performed.

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Section: Methodsmentioning

confidence: 99%

Quaternary Selenides EuLnCuSe3: Synthesis, Structures, Properties and In Silico Studies

Grigoriev

Solovyov

Русейкина

et al. 2022

IJMS

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“…Puzey [50]. The study of the EuErCuSe 3 magnetic susceptibility in weak magnetic fields, in the temperature range from liquid helium to room temperature, was carried out with the use of an original SQUID (superconducting quantum interference device) magnetometer [51,52]. The temperature dependences of the sample magnetic moment m were measured in two modes: (1) during cooling, in the absence of magnetic field (ZFC-zero-field cooling), and (2) when cooling in a magnetic field (FC-cooling in a nonzero magnetic field).…”

Section: Analysis Methodsmentioning

confidence: 99%

Synthesis, Structure, and Properties of EuLnCuSe3 (Ln = Nd, Sm, Gd, Er)

et al. 2021

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EuLnCuSe3 (Ln = Nd, Sm, Gd, Er), due to their complex composition, should be considered new materials with the ability to purposefully change the properties. Samples of the EuLnCuSe3 were prepared using Cu, rare earth metal, Se (99.99%) by the ampoule method. The samples were obtained by the crystallization from a melt and annealed at temperatures 1073 and 1273 K. The EuErCuSe3 crystal structure was established using the single-crystal particle. EuErCuSe3 crystallizes in the orthorhombic system, space group Cmcm, KCuZrS3 structure type, with cell parameters a = 4.0555 (3), b = 13.3570 (9), and c = 10.4602 (7) Å, V = 566.62 (6) Å3. In structure EuErCuSe3, erbium ions are coordinated by selenium ions in the octahedral polyhedron, copper ions are in the tetrahedral coordination, europium ions are between copper and erbium polyhedra layers and are coordinated by selenium ions as two-cap trigonal prisms. The optical band gap is 1.79 eV. At 4.7 K, a transition from the ferrimagnetic state to the paramagnetic state was detected in EuErCuSe3. At 85 and 293 K, the compound is in a paramagnetic state. According to XRPD data, EuLnCuSe3 (Ln = Nd, Sm, Gd) compounds have a Pnma orthorhombic space group of the Eu2CuS3 structure type. For EuSmCuSe3, a = 10.75704 (15) Å, b = 4.11120 (5) Å, c = 13.37778 (22) Å. In the series of EuLnCuSe3 compounds, the optical band gap increases 1.58 eV (Nd), 1.58 eV (Sm), 1.72 eV (Gd), 1.79 eV (Er), the microhardness of the 205 (Nd), 210 (Sm), 225 (Gd) 235 ± 4 HV (Er) phases increases, and the thermal stability of the phases increases significantly. According to the measurement data of differential scanning calorimetry, the EuNdCuSe3 decomposes, according to the solid-phase reaction T = 1296 K, ΔH = 8.2 ± 0.8 kJ/mol. EuSmCuSe3 melts incongruently T = 1449 K, ΔH = 18.8 ± 1.9 kJ/mol. For the EuGdCuSe3, two (Tα↔β = 1494 K, ΔHα↔β = 14.8 kJ/mol, Tβ↔γ = 1530 K, ΔHβ↔γ = 4.8 kJ/mol) and for EuErCuSe3 three polymorphic transitions (Tα↔β = 1561 K, ΔHα↔β = 30.3 kJ/mol, Tβ↔γ = 1579 K, ΔHβ↔γ = 4.4 kJ/mol, and Tγ↔δ = 1600 K, ΔHγ↔δ = 10.1 kJ/mol). The compounds melt incongruently at the temperature of 1588 K, ΔHmelt = 17.9 ± 1.8 kJ/mol and 1664 K, ΔHmelt = 25.6 ± 2.5 kJ/mol, respectively. Incongruent melting of the phases proceeds with the formation of a solid solution of EuSe and a liquid phase.

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“…Magnetization of valleriite samples was measured using a superconducting quantum interference device (SQUID) magnetometer [55], typically with a magnetic field of 500 Oe in field cooled, FC, and zero field cooled, ZFC, regimes in the temperature range from 4.2 K to 290 K. The magnetic moment was also determined as a function of the magnetic field varied from 0 to 800 Oe.…”

Section: Characterizationmentioning

confidence: 99%

Synthesis and characterization of nanoscale composite particles formed by 2D layers of Cu-Fe sulfide and Mg-based hydroxide

Mikhlin¹,

Борисов

Vorobyev³

et al. 2022

Preprint

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We introduce here a multifunctional material composed of alternating atomic sulfide sheets close to CuFeS2 and Mg-based hydroxide ones (valleriite), which are assembled due to their electric charges of opposite sign. Valleriite particles of 50-200 nm in the lateral size and 10-20 nm thick were synthesized via a simple hydrothermal pathway using various concentrations of precursors and dopants, and examined with XRD, TEM, EDS, X-ray photoelectron spectroscopy, reflection electron energy loss spectroscopy (REELS), Mössbauer, Raman and UV-vis-NIR spectroscopies, magnetic, dynamic light scattering, zeta potential measurements. The electronic, magnetic and optical characteristics are found to be critically dependent of the charge (electron density) at the narrow-gap sulfide layers containing Cu+ and Fe3+ cations, and can be tuned via the composition of hydroxide part. Particularly, substitution of Mg2+ with Al3+ increases the negative charge of the hydroxide layers and reduces the content of Fe3+-OH centers (10-45% of total iron); the effects of Cr and Co dopants entering both layers are more complicated. Mössbauer doublets of paramagnetic Fe3+ detected at room temperature transform to several Zeeman sextets at 4.2 K; the hyperfine fields up to 500 kOe and complex magnetic behavior, but not pure paramagnetism or antiferromagnetism, were observed for valleriites with the higher positive charge of the sulfide sheets, probably due to the depopulation of the minority-spin 3d states of S-bonded Fe3+ ions. Aqueous colloids of valleriite show optical absorption at 500 - 750 nm, which, along with the peaks at the same energies in REELS, may arise due to quasi-static dielectric resonance involving the vacant Fe 3d band and being dependent on the composition of both layers too. These and other findings call attention to the of valleriites as a new rich family of 2D materials for a variety of potential applications.

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High-Sensitivity Measurements of the Magnetic Properties of Materials at Cryogenic Temperatures

Cited by 13 publications

References 13 publications

Quaternary Selenides EuLnCuSe3: Synthesis, Structures, Properties and In Silico Studies

Quaternary Selenides EuLnCuSe3: Synthesis, Structures, Properties and In Silico Studies

Synthesis, Structure, and Properties of EuLnCuSe3 (Ln = Nd, Sm, Gd, Er)

Synthesis and characterization of nanoscale composite particles formed by 2D layers of Cu-Fe sulfide and Mg-based hydroxide

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