We report on structural, magnetic, and electrical properties of Sr-doped ${\mathrm{LaMnO}}_{3}$ single crystals for doping levels $0.4<~x<~0.85.$ The complex structural magnetic phase diagram can only be explained assuming significant contributions from the orbital degrees freedom. Close to $x=0.6$ a ferromagnetic metal is followed by an antiferromagnetic metallic below 200 K. This exists in monoclinic crystallographic structure. Following theoretical predictions this antiferromagnet...

The temperature-dependent Raman spectra of orthorhombic $R\mathrm{Mn}{\mathrm{O}}_{3}$ $(R=\mathrm{Pr},\mathrm{Nd},\mathrm{Sm},\mathrm{Eu},\mathrm{Gd},\mathrm{Tb},\mathrm{Dy},\mathrm{Ho},\mathrm{Y})$ were studied in the $5--300\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ temperature range. It was established that while materials with large ${R}^{3+}$ ionic radius ${r}_{R}$ and $A$-type antiferromagnetic order $(R=\mathrm{Pr},\mathrm{Nd},\mathrm{Sm})$ exhibit significant phonon softening other...

We report on structural, magnetic, electrical, and thermodynamic properties of Gd-doped $\mathrm{La}\mathrm{Mn}{\mathrm{O}}_{3}$ single crystals for Gd doping levels $0\ensuremath{\leqslant}x\ensuremath{\leqslant}1$. At room temperature, all the orthorhombic O' phase is indicative a strong Jahn-Teller distortion. All compositions are insulating. The magnetism ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Gd}}_{x}\mathrm{Mn}{\mathrm{O}}_{3}$ dominated by relatively...

We report on structural, magnetic, dielectric, and thermodynamic properties of (Eu:Y)MnO3 for Y doping levels 0 <= x < 1. This system resembles the multiferroic perovskite manganites RMnO3 (with R= Gd, Dy, Tb) but without interference magnetic contributions 4f-ions. In addition, it offers possibility to continuously tune influence A-site ionic radii. For small concentrations 0.1 we find a canted antiferromagnetic paraelectric groundstate. higher 0.3 ferroelectric polarization coexists with...

The magnetic, electric, magnetoelectric, and magnetoelastic properties of rare-earth ferroborates RFe3(BO3)4 (R=Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er) as well yttrium ferroborate YFe3(BO3)4 have been studied comprehensively. A strong dependence not only the magnetic but also magnetoelectric on type ion, specifically, its anisotropy, which determines structure large contribution to electric polarization, has found. This is manifested in temperature polarization below Néel point TN specific field...

We present a systematic electron-spin-resonance (ESR) study in single crystals of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{MnO}}_{3}(0&lt;~x&lt;~0.2).$ The temperature dependence the ESR linewidth marks all significant transitions between both orthorhombic ${(O}^{\ensuremath{'}},O)$ and rhombohedral (R) structural phases $T\ensuremath{-}x$ phase diagram. All peculiarities spectra for low x values within ${O}^{\ensuremath{'}}$ can be attributed to cooperative Jahn-Teller...

We have investigated the complex ac conductivity of for , temperatures and frequencies . In addition, results from dc measurements are presented. From frequency dependence we find hopping Anderson-localized charge carriers as dominant transport process in certain temperature composition ranges. deduce that, while Anderson localization is not driving mechanism metal-insulator transition observed this compound, it responsible high-resistivity regions at low doping levels temperatures. The...

The infrared and terahertz properties of ${\mathrm{GdMnO}}_{3}$ have been investigated as functions temperature magnetic field, with special emphasis on the phase boundary between incommensurate canted antiferromagnetic structures. heterogeneous reveals strong magnetodielectric effects, characterized by significant magnetoelectric contributions to static dielectric permittivity existence electrically excited magnons (electromagnons). In commensurate constant electromagnons are suppressed....

We present a detailed dielectric study of the relaxation effects that occur in several perovskite rare-earth manganites, including multiferroics ${\mathrm{TbMnO}}_{3}$ and ${\mathrm{DyMnO}}_{3}$. demonstrate strong magnetocapacitive effects, observed for electrical fields $\mathbf{E}\ensuremath{\parallel}\mathbf{c}$, are nearly completely governed by magnetic-state induced changes parameters. The multiferroic materials, which undergo transition into spiral magnetic state, show qualitatively...

Magnetic and magnetoelectric excitations in the multiferroic TbMnO3 have been investigated at terahertz frequencies. Using different experimental geometries we can clearly separate electroactive (electromagnons) from magnetoactive modes, i.e., antiferromagnetic resonances. Two resonances were found to coincide with electromagnons. This indicates that both belong same mode electromagnons be excited by a magnetic ac field as well. In spite of 90 degrees rotation cycloid external fields, are...

Apart from being so far the only known binary multiferroic compound, CuO has a much higher transition temperature into state, 230 K, than any other material in which electric polarization is induced by spontaneous magnetic order, typically lower 100 K. Although magnetically ferroelectricity of firmly established, no magnetoelectric effect been observed as direct crosstalk between bulk magnetization and counterparts. Here we demonstrate that high fields about 50 T are able to suppress helical...

We report on susceptibility, magnetization, magnetoresistance, and ultrasonic studies of La1-xSrxMnO3 for x⩽0.2. The magnetic susceptibilities in the different high-temperature paramagnetic phases are studied detail. provide experimental evidence occurrence short-range ferromagnetic order within phase. Furthermore, we can exclude possibility electronic phase separation x<0.1. Variable-range-hopping conductivity dominates magnetically ordered phases. From anomalies at structural transitions,...

A brief review is presented of a novel method high-frequency magnetic resonance spectroscopy, which sweeps the frequency at fixed field, including zero field. We describe main features this frequency-domain spectrometer works in spectral range from 30 GHz to 1.5 THz and fields up 8 T; temperature can be as low 0.4 K. The versatility technique demonstrated by means number examples field molecular magnetism.

The ground-state properties of the perovskites ${\mathrm{PrMnO}}_{3}$ and ${\mathrm{NdMnO}}_{3}$ were investigated by magnetization, magnetic ac susceptibility, specific heat measurements. A strongly anisotropic behavior has been detected for temperatures below antiferromagnetic phase transition ${T}_{\mathrm{N}}\ensuremath{\approx}100\mathrm{K}.$ susceptibility weak spontaneous ferromagnetic moment appear to be different in both compounds due rare-earth contributions. shows strong...

Transitions inside the ground S = 10 multiplet of magnetic clusters Mn12-Ac have been observed in submillimeter transmission spectra measured by means a quasi-optical backward-wave-oscillator technique frequency range ν 3–33 cm−1. The temperature dependence resonance frequencies, linewidths and mode contributions to permeability T 3–35 K are consistent on whole with spin state split tetragonal crystal field. However, some deviations between calculated at high temperatures suggest presence...

We review terahertz experiments on magnetoelectric excitations in rare earth multiferroic manganites RMnO 3 with R = Gd, Tb, Dy, (Eu:Y).In all these compounds characteristic of the novel type, called electromagnons, have been observed for frequencies 10 cm -1 < ν 30 .From spectroscopic point view electromagnons are responsible effects and, contrary to magnons, excited only by electric components electromagnetic wave.In compositions appear as a broad Debye-like contribution sinusoidally...

Dielectric permittivity spectra of yttrium-doped $\mathrm{Eu}\mathrm{Mn}{\mathrm{O}}_{3}$ in the composition range $0\ensuremath{\leqslant}x\ensuremath{\leqslant}0.5$ have been investigated terahertz frequency range. Magnetoelectric contributions to were observed all compositions for ac electric fields parallel crystallographic $a$ axis. Well-defined electromagnons exist $x\ensuremath{\geqslant}0.2$ close...