Effect of (Cu/Fe)O5 bipyramid size and separation on magnetic and dielectric properties of rare earth layered perovskite LaBaCuFeO5 and LuBaCuFeO5

Abstract

We report structural, magnetic and dielectric properties of layered perovskite materials LnBaCuFeO 5 (Ln = La and Lu). LaBaCuFeO 5 shows magnetic cluster glass behavior below 60 K owing to the competing ferromagnetic and antiferromagnetic exchange interactions. Glassy dynamics of electric dipoles has also been observed in the vicinity of the magnetic glass transition temperature. The presence of significant coupling between spin and polar degrees of freedom results in the multiglass feature in LaBaCuFeO 5 . The LuBaCuFeO 5 compound undergoes YBaCuFeO 5 like commensurate to incommensurate antiferromagnetic transition at 175 K. Large magnetic irreversibility below 17 K in this compound suggests the presence of strong spin anisotropy. In addition, in this compound the interaction between the dipoles is not strong enough, which results in the absence of glassy dynamics of electric dipoles. The contrasting behavior of two compounds is possibly due to variation in the ferromagnetic and antiferromagnetic interactions along c-axis, which is the manifestation of structural modification arising out of the difference in the ionic radii of La and Lu.

Low temperature magnetic and dielectric properties of LnBaCuFeO5 (Ln =Nd, Eu, Gd, Ho and Yb)

“…The obtained parameters are tabulated in Table 1. For GdBaCuFeO 5 , HoBaCuFeO 5 , YbBaCuFeO 5 and EuBaCuFeO 5 ; some parameters are taken from Ref [14] and [15], while for YBaCuFeO 5 , LaBaCuFeO 5 and LuBaCuFeO 5 some parameters are taken from Ref [9] and [13] for the sake of comparison. LnBaCuFeO 5 are layered perovskite compound with tetragonal structure of P4mm space group [1,2,16,17].…”

“…Various rareearth ions at the A-site can change the chemical pressure and it may result in interesting dielectric properties in the respective compounds. A detailed comparative study of the contrasting physical properties exhibited by rare earth layered perovskite LaBaCuFeO 5 and LuBaCuFeO 5 has been carried out [13]. Recent investigations on HoBaCuFeO 5 , GdBaCuFeO 5 and YbBaCuFeO 5 reveal that the observed upturn in the heat capacity at low temperatures in these compounds is attributed to the Schottky anomaly [14,15].…”

Heat Capacity of Layered Perovskite Compounds: EsBaCuFeO5 (Es = Ho, Gd, and Yb)

“…Perovskite materials have an important role in electronic applications due to their electrically insulating properties and high chemical stability. In this regard, the compound YBaCuFeO 5 has been widely studied for its multiferroic properties because it is observed in both dielectric and magnetic transitions around 200 K. [1][2][3][4][5][6][7] Therefore, YBaCuFeO 5 is an interesting candidate to study the possibility magnetodielectric coupling near room temperature. [1,2,[7][8][9][10][11] In recent years, the detailed studies of these compounds have been carried with various rare-earth ions.…”

“…[1,2,[7][8][9][10][11] In recent years, the detailed studies of these compounds have been carried with various rare-earth ions. [5][6][7]11,12] Especially, the layered perovskite compounds, with the general formula XX'YY'O 5 (X, X' are alkali/rare-earth metals and Y, Y' are transition metals with same or different ions), have been investigated for their interesting magnetic, electronic, and multiferroic properties. [1,2,[9][10][11][12][13][14][15] The physical properties of these rare-earth layered perovskite compounds are highly connected to the structure and the expansion of the unit volume and display contrasting behavior.…”

“…[1,2,[9][10][11][12][13][14][15] The physical properties of these rare-earth layered perovskite compounds are highly connected to the structure and the expansion of the unit volume and display contrasting behavior. [6] Moreover, according to the size of rareearth ions, the compounds XX'YY'O 5 have interesting dielectric properties: increase of the dielectric constant at high temperature, the presence of Schottky anomaly at low temperature, absence of any magnetic transition, contrasting physical properties, etc. Thermodynamic, structural, and magnetic properties of XX'YY'O 5 compounds have been investigated in the study by Lal et al [7] In heat capacity studies of these compounds at low temperature., they indicated the presence of Schottky anomaly.…”