Temperature dependent structural properties of Mn_1.90M_0.10O₃ (M = Cr and Fe)

Abstract

The polycrystalline samples of Mn1.90Cr0.10O3 (MCO) and Mn1.90Fe0.10O3 (MFO) have been investigated for their temperature dependent magnetic and structural properties. The Cr and Fe substitutions have significant effect on the magnetic and structural properties of Mn2O3. Like pristine Mn2O3, the Cr and Fe substituted samples MCO and MFO also exhibit two antiferromagnetic transitions; one at ~77 K, ~80 K, respectively and another at ~40 K. Our room temperature synchrotron x-ray powder diffraction (SXRD) results confirm that both the MCO and MFO samples crystallize in cubic symmetry. The temperature dependent SXRD results demonstrate the cubic to orthorhombic structural transition for the studied samples. The pristine Mn2O3 shows cubic to orthorhombic transition around 310 K, whereas this structural transition shifted towards lower temperature side with these substitutions i.e., around 240 K for MCO and 260 K for MFO. Interestingly, the centrosymmetric Pcab to non-centrosymmetric Pca21 change in symmetry is also resolved at the ferroelectric ordering temperature for MCO.

Na3[Al2B6P4O22(OH)3](H2O)6 and Na3[Al2BP2O11](H2O)0.5: Two Remarkable Complex Aluminum Borophosphates

“…This remarkable lower framework density of ABPO1 is well within the zeolite range and comparable with those extraordinary zeolite materials reported previously. 43,57,58 From the natural tiling illustration, the CBU of the ABPO1 framework is [6 8 63,64 (Table S1). The oxidation state of the B cation is 3+, the P cation is 5+, the Al cation is 3+, and the Na cation is 1+ based on the BVS values that are ∼2.93, ∼ 5.24, ∼ 3.12, and ∼1.10, respectively.…”

“…Borophosphates have at least one BO 3 (or BO 4 ) group and one PO 4 tetrahedron share a bridged O atom, whereas the BO 3 /BO 4 and PO 4 anionic units are isolated from each other in the structure of borate phosphates. 4,7 A number of borophosphate materials have been prepared, for example, M 2 BP 3 O 12 (M = Fe, Cr) shows interesting magnetic properties, 8 Ba 8 {Ni, Mn} 4 [BP 3 O 11 (OH) 2 ] 4 has a new "anti-zeolite" structure with a positively charged framework, 9 MBPO 5 (M = Sr and Ba), 10 Na 3 Cd 3 B(PO 4 ) 4, 11 AMBP 2 O 8 (A = K, M = Sr, Ba; A = K, Rb, M = Pb), 12−15 and β-Zn 3 (BO 3 )(PO 4 ) 16 are potential nonlinear optical materials. The Eu 2+ -doped Ba 3 BP 3 O 12 is a new scintillation material.…”

“…A number of borophosphate materials have been prepared, for example, M 2 BP 3 O 12 (M = Fe, Cr) shows interesting magnetic properties, Ba 8 {Ni, Mn} 4 [BP 3 O 11 (OH) 2 ] 4 has a new “anti-zeolite” structure with a positively charged framework, MBPO 5 (M = Sr and Ba), Na 3 Cd 3 B­(PO 4 ) 4, AMBP 2 O 8 (A = K, M = Sr, Ba; A = K, Rb, M = Pb), − and β-Zn 3 (BO 3 )­(PO 4 ) are potential nonlinear optical materials. The Eu 2+ -doped Ba 3 BP 3 O 12 is a new scintillation material .…”