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The solid-state reaction technique was employed to synthesize compounds of YMnO3 (YMO) and YMn1-xCoxO3 (YMCO) with various Co doping levels (x = 0.01, 0.10, 0.20, and 0.40), where Co atoms partially substituted Mn sites. XRD studies confirmed the presence of two phases, YMO and Y0.98CoO3 (YCO), for doping ratios above x = 0.10. Additionally, an increase in crystalline size was observed with cobalt substitution. Surface characteristics of synthesized pellets were examined using scanning electron microscopy (SEM), revealing a less porous structure with cobalt doping. XPS analysis elucidated valence states, showing the presence of both Mn3+ and Mn4+, as well as Co2+ and Co3+. The x = 0.20 and 0.40 Co-doped samples exhibited lower grain and grain boundary energies compared to other samples, such as a decrease from 0.556 eV (undoped) to 0.195 eV (x = 0.20). Moreover, the dielectric constants of x = 0.20 and 0.40 cobalt-doped samples (around 320) significantly surpassed the undoped sample (around 22) at 106 Hz and 100 °C. The x = 0.20 cobalt-doped sample demonstrated the highest conductivity at 100 °C and 106 Hz (31 × 10–4 S/cm). FT-IR analysis provided insights into vibration and bending modes, and frequency- and temperature-dependent electrical features were investigated. It was observed that a single conduction model is insufficient to fully explain the conduction mechanism in these samples. [ABSTRACT FROM AUTHOR]

The magnetic and electrical features of rare-earth orthoferrites, RFeO3, can be modified via substitution of different elements into R and/or Fe sites. In the present investigation, the electrical properties of YbFeO3 (YbFO) were inspected with cobalt (Co) doping into Fe sites by various mole %. The crystalline morphology of the obtained YbFeO3 and YbFe1-xCoxO3 (YbFCO) (x = 0.01, 0.05, 0.10) powders was studied by X-ray diffractometer (XRD) and infrared (IR) spectroscopy measurements. Surface structure of the obtained powders was scrutinized by scanning electron microscope (SEM). Furthermore, X-ray photoelectron spectroscopy (XPS) was employed for identifying the oxidation states of the synthesized components. Dielectric/impedance spectroscopy measurements were conducted to investigate electrical features of the YbFO and YbFCO powders at different frequencies and temperatures. It turned out that the conductivity and the dielectric constant of undoped YbFO can be boosted by Co doping into Fe sites. The present study underscored that multiple models need to be taken into account for the studied materials to explain conduction mechanism. [ABSTRACT FROM AUTHOR]

Abstract Due to their novel electrical, magnetic and optical features, many research groups have studied orthoferrites broadly in the literature. We have examined the electrical features of YbFeO 3 (YbFO) and YbFe 1-x Ir x O 3 (YbFIO) (x = 0.01 and 0.10) powders. The crystal structure of the synthesized powders was examined via X-ray diffractometer (XRD) and infrared spectroscopy (IR) measurements. Surface morphologies of the obtained pellets were scrutinized by scanning electron microscope (SEM). Moreover, the oxidation states of the constituted elements were inspected by X-ray photoelectron spectroscopy (XPS). Electrical properties such as electrical modulus, dielectric constant and conductivity of the powders were documented at various frequencies and operating temperatures via dielectric/impedance spectroscopy measurements. It was shown that dielectric constant and conductivity of 1 mole % doped YbFO sample are higher than the other samples. In addition, the conductivity studies revealed that more than one conduction model needs to be considered for understanding the conduction mechanism. Highlights • YbFeO 3 (YbFO) and Ir doped YbFO were prepared by solid-state reaction. • YbFO and Ir doped YbFO have multiple relaxations. • Ir doped YbFO has lower activation energy than the parent YbFO. • Dielectric constant and electrical conductivity were improved after Ir doping. • Conduction mechanism can be explained by multiple models depending upon frequency and temperature. [ABSTRACT FROM AUTHOR]

Due to its electrical, magnetic, and optical characteristics, LuFeO 3 (LFO) has caught the scientific community's interest. In this study, the powders of LFO, LuFe 0.95 Co 0.05 O 3 , and LuFe 0.90 Co 0.10 O 3 samples were prepared by using the well-known solid-state approach. The crystalline structure of the fabricated samples was examined by an X-ray diffractometer (XRD). It was found that the samples display secondary phases such as Lu 2 O 3 , Lutetium Tetraoxodiferrate, and Wüstite. It was shown by scanning electron microscope (SEM) that particle size decreases with Co doping. X-ray photoelectron spectroscopy (XPS) determined oxidation states for Fe and Co. It was presented that Fe has a mixture of 2 + and + 3 valance states in the LFO sample. Although LuFe 0.95 Co 0.05 O 3 has only the 3 + state, LuFe 0.90 Co 0.10 O 3 sample has coexisting metallic and 3 + states. The conductivity and dielectric constant of the undoped LFO sample were higher than those of Co doped LFO samples. A decrease in both the dielectric constant and conductivity was associated with a lack of Fe2+ ions and lattice distortions. Furthermore, it was argued that several conduction models must be developed to explain the conduction process in the analyzed samples. Magnetic experiments using a vibrating sample magnetometer (VSM) revealed that Co doping raises M r values. We discuss that this increase in M r values could be related to i) variations in the inclined angles of Fe3+ moments and ii) the growth of magnetocrystalline anisotropy's energy. • SEM images showed that particle size shrinks after the doping process. • LFO and Co doped LFO samples showed both grain and grain boundary relaxation depending on the M″ vs. f plots. • Dielectric constant and electrical conductivity decline after Co substitution. • Conduction mechanism can be clarified by various models depending on frequency and temperature. • Co doped materials have higher M r values than the LFO sample. [ABSTRACT FROM AUTHOR]

Previously, it has been demonstrated the electrical and magnetic properties of YMnO 3 (YMO) can be tuned with substitution of different elements into Y and/or Mn sites. In this study, the electrical properties of YMO were explored via substituting osmium (Os) into Mn site with various mol %. The crystalline morphology of synthesized YMnO 3 and YMn 1-x Os x O 3 (YMOO) (x = 0.01, 0.05, 0.10) powders were characterized with X-ray diffractometer (XRD) and infrared spectroscopy (IR) measurements. The crystalline morphology of synthesized powders was studied via scanning electron microscope (SEM). Oxidation states of constituent elements have been examined by X-ray photoelectron spectroscopy (XPS). Electrical properties of YMO and YMOO powders were investigated by dielectric/impedance spectrometer at various temperatures and frequencies. Electric modulus measurements unveiled that for each of x = 0, 0.01 and 0.05 samples there are three relaxation peaks while x = 0.10 sample shows four relaxation peaks. It has been shown that dielectric constant and conductivity properties of parent YMO can be enhanced via Os substitution, particularly, 10 mol % Os doped sample has the highest dielectric constant and conductivity at various temperatures and frequency regions. Moreover, the conduction mechanisms were also examined. It turned out that in order to explain conduction mechanism, multiple models need to be considered in the studied materials. [ABSTRACT FROM AUTHOR]

Solid-state technique was utilized to obtain the LuFeO 3 (LFO) and LuFe 1−x Os x O 3 (LFOO) compounds having x = 0.05 and 0.10. The orthorhombic structure and the presence of secondary phases in the studied samples have been unveiled by X-ray diffractometer (XRD) investigations. The scanning electron microscope (SEM) examinations have unveiled that not only the particle sizes enlarge with Os substitution but also particle agglomeration takes place. The X-ray photoelectron spectroscopy (XPS) investigations have exposed the oxidations of Fe as 2 + and 3 + for the LFO sample, 3 + for 5 mol% Os substituted specimen and mix of 2 + and 3 + for 10 mol% Os doped sample. In addition, it was shown that Os has 4 + oxidation state in the doped samples. Dielectrical and electrical conductivity studies of the obtained ceramics conducted between − 100 °C (173 K) up to 100 °C (373 K) with 20 °C temperature pace have shown that the undoped sample has much higher values than the Os doped samples. Such differences have been ascribed to the absence of Fe2+ ions and lattice distortions in the Os doped samples. In addition, it was realized that different conduction models need to be adapted to comprehend the conduction mechanism in the examined specimens. • LuFeO 3 (LFO) and Os doped LFO were synthesized by solid-state reaction. • Os substitution lowers the ratio of Fe2+ ions in LFO structure. • LFO and Os doped LFO have multiple relaxations. • Dielectric constant and electrical conductivity were deteriorated after Os substitution. • Conduction mechanism can be comprehended by multiple models depending upon frequency and temperature. [ABSTRACT FROM AUTHOR]

• LuFeO3 (LFO) and Ir doped LFO were prepared by solid-state reaction. • Ir substitution lowers the ratio of Fe2 + ions in LFO structure. • LFO and Ir doped LFO have multiple relaxations. • Dielectric constant and electrical conductivity were deteriorated after Ir doping. • Conduction mechanism can be explained by multiple models depending upon frequency and temperature. Rare-earth ferrites have been intensively investigated owing to their magnetic, electrical, and optical features in the literature. The present quest goals to examine the electrical properties of LuFeO 3 (LFO) and LuFe 1−x Ir x O 3 (LFIO) ceramics with different mol%, x = 0.05 and 0.10. X-ray diffractometer (XRD) method was utilized to identify the crystal nature of the obtained powders. The scanning electron microscope (SEM) was exploited to examine the surface topography of the fabricated pellets. X-ray photoelectron spectroscopy (XPS) was employed to find out the valence states of lutetium (Lu) (data is not presented here), iron (Fe), and iridium (Ir). Electrical modulus, dielectric constant, and conductivity of LFO and LFIO ceramics were detailed by dielectric/impedance spectroscopy measurements, which were performed at between − 100 °C (173 K) up to 100 °C (373 K) with 20 °C temperature step. It was exhibited that the undoped LFO has a higher dielectric constant and conductivity than the Ir doped samples. Such a decrement in both dielectric constants and conductivity was related to i) reduction in the ratio of Fe2+ ions and ii) defects and/or distortion in the LFO structure due to Ir substitution. [ABSTRACT FROM AUTHOR]

Fig. Comparison of real part of the dielectric constant for LaCrO 3 , LaCr 0.99 Os 0.01 O 3 , LaCr 0.97 Os 0.03 O 3 , and LaCr 0.95 Os 0.05 O 3 at a) -100 °C, b) 20 °C and c) 100 °C. • The electrical properties of LaCrO 3 were modified by doping of Os transition into Cr atom. • Os-doped LCO materials were synthesized by solid-state reaction technique. • A wide range of investigation on doping evaluation of Os into Cr cation in LCO perovskite structure has been performed at -100 °C to +100 °C temperature range. • The conductivity and the dielectric values of the LCO improve with Os dopant. • Various conduction model needs to be considered to explain the conduction in the undoped and Os doped LCO compounds. This study aims to investigate the electrical properties of LCO compound under Os doping into Cr sites with different substitution levels. The crystalline structure of LaCrO 3 and LaCr 1-x Os x O 3 (LCOO) (x = 0.01, 0.03, 0.05) was inspected with X-ray diffractometer (XRD). Scanning electron microscope (SEM) was utilized to observe the particle/powder morphology. Moreover, the valence states of the elements were investigated by X-ray photoelectron spectroscopy (XPS). The electrical modulus, dielectric constant and conductivity of the LCO and LCOO pellets were detailed by dielectric/impedance spectroscopy studies at different frequencies and temperatures. The temperature dependent power law exponent, calculated through conductivity versus temperature measurements, exhibited that different conduction models are needed to consider for the conductivity mechanism. Furthermore, it has been realized that the activation energies determined from electrical modulus and dc conductivity are close to each other. [ABSTRACT FROM AUTHOR]

Fig. The Absorption spectra of YbFeO 3 (a) and Co doped YbFeO 3 (b and c) thin films. Inset figures represent the Tauc plots of thin films with the calculated band gaps. • YbFeO 3 (YbFO) and Co doped YbFO thin films were prepared by magnetron sputtering. • The band gap of YbFO has lowered from 2.1 eV to 1.72 eV via Co doping into Fe sites. • Optical dielectric constant is improved by Co doping. • Optical electrical conductivity was enhanced after Co substitution. It has been shown that the band gap engineering plays vital role in the designing of new semiconductors. Therefore, many research groups have focused on various techniques to tune the band gap such as chemical doping and strain energy. In the present work, polycrystalline YbFeO 3- ẟ (YbFO) and YbFe 1-x Co x O 3- ẟ (YbFCO) (x = 0.01 and 0.10) thin films were grown on indium tin oxide (ITO) substrates at 500 0C by magnetron sputtering technique. The crystalline orientation of the thin films has been studied by XRD. SEM and AFM have been utilized in the surface topographical investigations and XPS analysis was carried out in order to reveal the oxidation states of elements in studied materials. It has been shown that the optical band gap YbFO can be tuned from 2.1 eV to 1.72 eV via Co doping into Fe sites. Furthermore, diffuse reflectance spectroscopy (DRS) has been employed to study reflectance %, refractive index (n), extinction coefficient (k), real and imaginary parts of dielectric constant and conductivity. [ABSTRACT FROM AUTHOR]