Structural and micro-Raman studies of DyMnO₃ with potassium substitution at the Dy site

Abstract

We synthesize a new series of compounds, Dy1−xKxMnO3 (x = 0.1, 0.2 & 0.3) and report the structural and spectroscopic properties of the new compounds in comparison to DyMnO3.

Effects of Dy sub lattice dilution on transport and magnetic properties in Dy1-xKxMnO3

“…23 Structure and phase integrity of the compounds were examined by X-ray diffraction technique at room temperature. The electrical resistivity of DKMO was measured by a standard four-probe method using a dipstick arrangement in the limited temperature range 160 K -300 K on account of their very high resistivity below ∼160 K. Time Electronics 9818 was used to apply a constant current, and Agilent 34420A nano voltmeter was used to measure the voltage developed across the electrical leads in response to the constant current.…”

“…Octahedral distortions were found to reduce with a decrease in the concentration of JT ions as a result of potassium substitution. 23 The electrical resistivity of DKMO compounds as a function of temperature, (Fig. 1) shows that the parent compound, DMO which has only trivalent JT active manganese (Mn 3+ , t 3 g e 1 g ) ions displays semiconducting nature in the entire temperature range.…”

“…Mixed oxidation states of Mn ions in DKMO were evident from X-ray photoelectron spectroscopy. 23 In perovskite manganites, it is well known that Double Exchange (DE) interaction between Mn 3+ and Mn 4+ ions through an oxygen ion is responsible for ferromagnetic metallic properties. 12 Although heterovalent Mn ions with (e 1 g ) and without (e 0 g ) mobile electrons are available in substituted oxides, the resistivity of these oxides showed semiconducting behavior in the whole temperature range.…”

“…23 The powder X-ray diffraction data of DMO along with lattice parameters are reported in International Centre for Diffraction Data (ICDD), 2016. 24 Structural distortions due to the movement of oxygen ions towards the centre of manganese oxide octahedra as observed in the pure oxide, DMO were attributed to the smaller Dy ion at A-site in ABO 3 (A: transition/rare earth metal, B: transition/alkaline earth metal ion) perovskites and Jahn-Teller (JT) distortions caused due to Mn 3+ ions.…”

“…22 In view of the multi functional properties of these materials, we have undertaken monovalent ionic substitution at Dy site in DMO and carried out measurements of transport and magnetic properties of the new series of compounds in Dy 1-x K x MnO 3 whose structural properties were recently reported by us. 23 …”