xCrxO3 System Research Articles

Tuning Magnetic and Semiconducting Properties of Cr-Doped CaTiO3 Perovskites for Advanced Spintronic Applications

The physical properties of perovskite-type materials are sensitive to their chemical composition and crystallographic structure, which makes them highly versatile for various advanced technological applications. In this theoretical study, density functional theory (DFT) is employed to investigate the electronic properties of the perovskite-like material CaTiO3, focusing on the substitution of Ti4+ with the magnetic transition metal Cr4+. The results reveal a systematic increase in the effective magnetic moment and a gradual decrease in the bandgap with increasing Cr4+ content in the CaTi1−xCrxO3 system (x = 0.0, 0.25, 0.5, 0.75, 1.0). The interactions between electronic orbitals associated with Ti-O-Cr inter-octahedral bonds modify the magnetic response of the material, leading to hybridizations between valence and conduction states that alter its semiconductor character. This tunability in electronic and magnetic properties underscores the potential of these materials for applications in spintronics. This study offers novel insights into the design of new magnetic semiconductor materials with tailored functionalities, contributing to the development of next-generation spintronic devices.

Calculation of special spin behavior of Dy3+ in DyFe1−xCrxO3 system by molecular field model

Calculation of special spin behavior of Dy3+ in DyFe1−xCrxO3 system by molecular field model

Observation of giant magnetocaloric effect in EuTi1-xCrxO3

The magnetic properties and magnetocaloric effect in EuTi1−xCrxO3 (x = 0, 0.02, 0.04, 0.1) compounds are investigated. The magnetic ground state (AFM) of pure EuTiO3 can be significantly changed to be FM with slight Cr-doping. A giant reversible MCE and large RC in EuTi1−xCrxO3 compounds were observed. The value of −ΔSMmax reaches to 40.3 J/kg K for EuTiO3 under the magnetic field change of 5 T. Especially, under the magnetic field changes of 1 and 2 T, the values of −ΔSMmax are evaluated to be 12.5 and 22.5 J/Kg K and the maximum values of RC are 64 and 127 J/kg, without magnetic and thermal hysteresis for EuTi1−xCrxO3 system. Therefore, the giant reversible MCE and large RC make the EuTi1−xCrxO3 compounds could be considered as a good candidate material for low-temperature and low-field magnetic refrigerant.

Structural and magnetic properties of La1−xCexFe1−xCrxO3 orthoferrite prepared by co-precipitation method

Nanocrystalline orthoferrites with the composition of La1−xCexFe1−x CrxO3 where (x=0, 0.1, 0.15 and 0.2) were prepared by co-precipitation method. The structural and magnetic properties of the La1−xCexFe1−xCrxO3 system have been investigated. X-ray diffraction showed the formation of orthorhombic structure with space group Pnma for different compositions. With increasing Ce and Cr content, lattice parameters a and c were found to decrease while b increases, resulting in a decrease of the unit cell volume. The crystallite size was calculated from XRD data and compared with that obtained from TEM micrographs. Vibrating sample magnetometer measurements reveal an enhancement in the coercivity (Hc) with increasing Ce and Cr content and reduction of saturation magnetization (Ms) and remnant magnetization (Mr) up to x=0.15 and increases with further increases of x. The magnetic susceptibility measurements vs. temperature showed canted-antiferromagnetic (AFM) in which the Neel temperature is increasing with Ce and Cr content.

Perovskites Bi0.8La0.2FeO3 and Bi0.8La0.2Fe0.95Cr0.05O3: Crystal structure and magnetic and charge states of iron ions

Perovskites of the Bi0.8La0.2Fe1 − xCrxO3 system (x = 0, 0.05) were investigated by Mossbauer spectroscopy in the temperature range of 298–800 K. The samples were fabricated by solid-state synthesis and had a rhombic structure. Iron ions in Bi0.8La0.2FeO3 and Bi0.8La0.2Fe0.95Cr0.05O3 are situated in trivalent states. The magnetic transition temperatures (the Neel temperatures TN) TN = 677.5 ± 2.5 K for Bi0.8La0.2FeO3 and TN = 647.6 ± 2.5 K for Bi0.8La0.2Fe0.95Cr0.05O3 are measured. The substitution of trivalent iron ions from trivalent chromium ions in the amount x = 0.05 in Bi0.8La0.2Fe0.95Cr0.05O3 perovskite decreases the hyperfine magnetic field at nuclei 57Fe in Fe+3-O-Cr+3 chains by 30 kOe.

Low-temperature transitions in the SrMo1−xCrxO3−δ (x = 0.1 and 0.2) perovskite system

In this paper we have studied the effect of Cr doping on the structural and electronic transport properties in 4d perovskites SrMo1−xCrxO3 (x=0, 0.1 and 0.2). Polycrystalline samples were prepared by a soft chemistry procedure followed by thermal treatments in a 5%H2 atmosphere. X-ray and neutron powder diffraction analysis were used to identify the purity of the samples and provide an accurate description of the crystal structure features (GdFeO3 type). The Cr doping at B position does not change the space group of the samples; they are all cubic, space group Pm-3m, at room temperature. However, upon cooling down the samples two structural phase transitions appear, the first from cubic Pm-3m structure to a tetragonal structure defined in I4/mcm close to 240K, and the second to an orthorhombic Imma phase below 100K. Cr substitution drives the SrMo1−xCrxO3 system from a Pauli-paramagnetic state to a weak ferromagnetic state combined with predominant antiferromagnetic interactions; the susceptibility and the saturation magnetization increases monotonically with increasing the Cr-doping content.

Magnetic behavior induced by Cr doping in SrMoO3 from first‐principles studies

AbstractThe electronic structure and magnetic properties of SrMo1 − xCrxO3 with x of 0, 0.125, 0.25, and 0.5 have been studied using ab initio density‐functional calculations with the LSDA + U method. The results suggest that light Cr doping can drive the SrMo1 − xCrxO3 system from the PM to the FM state. It is found that the spin‐dependent hybridizations between Cr and Mo (via O) may induce Mo moments in Cr‐doped SrMoO3. However, the effective moments of Mo ions are negligibly small for x = 0.125, 0.25. The FM behavior is contributed by the spin‐polarized Cr atoms. With more increase of Cr atoms, for x = 0.5, a negative moment about 0.32 µB/Mo is induced by Cr atom which is coupled antiferromagnetically to the Cr moment. Meanwhile, the half‐metallic nature is observed in which the spin‐down channel has a conducting behavior, while the spin‐up channel shows an isolated feature with a gap of ∼1.82 eV. The Mo 4d electrons contribute to the conducting behavior and there are practically no Cr‐d states around the Fermi level.

Spin glass behavior in the half doped Pr0.5Ca0.5Mn1−xCrxO3 system

Abstract Systematic study on the magnetic properties has been performed for the Cr-doped Pr0.5Ca0.5Mn1−xCrxO3 (x=0, 0.01, 0.03, 0.05, 0.07 and 0.10) system. For the samples with x=0.01 and 0.10, spin glass behavior is observed, which is resulted from different magnetic ground states. The present experiment establishes that the compound with x=0.01 shows a spin glass behavior in the background of an antiferromagnetic (AFM) matrix, while the spin glass behavior appears in the background of a ferromagnetic (FM) host phase for x=0.10. It is believed that the spin glass state accompanied by multiple magnetic transitions is resulted from the competing interaction between AFM matrix and FM phase induced by Cr-doping. The magnetic ground state in the manganites is strongly associated and very sensitive to Cr dopant.

Ferromagnetism in Cr substituted SrMoO3 system

Systematic studies of structural, magnetic, electric transport, and specific heat properties have been performed on lightly Cr-doped molybdates SrMo1−xCrxO3 (0⩽x⩽0.10). Based on the analysis of structural parameter variations, the valence state of the doped Cr ions in SrMo1−xCrxO3 system is suggested to be +2. Cr substitution as low as x=0.025 is sufficient to drive SrMo1−xCrxO3 system from the Pauli-paramagnetic state to a ferromagnetic state. The Curie temperature TC increases monotonically with increasing Cr-doping content. All samples exhibit metalliclike transport behavior in the whole studied temperature range except for the x=0.10 sample. The magnitude of the resistivity increases monotonically with increasing Cr-doping level. The evolution of the magnetic and resistive properties with Cr-doping content x may be related to the narrowed d-band width due to Cr substitution. In addition, the temperature dependence of specific heat for all samples has also been studied.

Cr-doping-induced phase separation and MR effect in the manganite Pr0.5Ca0.5Mn1−xCrxO3 system

Systematic study on magnetic and electrical transport properties has been performed on the Cr-doped Pr0.5Ca0.5Mn1−xCrxO3 (x=0, 0.03, 0.05, 0.07, 0.10) system. The results show that Cr-doping leads to melting of the charge ordering and induces phase separation. For the sample x=0.10, reentrant spin glass behavior is observed and the slowing down model is applicable. The reentrant spin glass behavior and the phase coexistence of charge ordering (CO) and the ferromagnetic metal phase (FMM) are responsible for the changing magnetoresistance effect of the system. The phase separation or coexistence of the CO and FM phase induced by Cr-doping plays an important role in the low temperature properties for the system.

Tuning colossal magnetoresistance response by Cr substitution in La0.67Sr0.33MnO3

We have studied the effects of Cr substitution in the perovskite La0.67Sr0.33MnO3 on the magnetic, electrical transport, and magnetoresistance properties. Cluster glass behaviors have been observed in the La0.67Sr0.33Mn1−xCrxO3 system. The most interesting feature is that extraordinary transport and colossal magnetoresistance (CMR) behaviors, characterized by double peaks, were observed with Cr substitution. When 0.1⩽x⩽0.2, the temperature range of CMR response is greatly broadened, from the lowest temperature to above room temperature. These results suggest that Cr substitution can be a potent way in tuning CMR response and also imply a ferromagnetic interaction similar to double exchange occurs between Mn and Cr.