Symmetry-mode analysis of the phase transitions in SrLaZnRuO6 and SrLaMgRuO6 ordered double perovskites

Iturbe-Zabalo, E.; Igartua, J.M.; Gateshki, M.

doi:10.1107/S0021889813013253

Symmetry-mode analysis of the phase transitions in SrLaZnRuO₆ and SrLaMgRuO₆ ordered double perovskites

E. Iturbe-Zabalo, J. M. Igartua and M. Gateshki

The crystal structures of double perovskites SrLaMRuO₆ (M = Zn and Mg) have been studied using X-ray and neutron diffraction data. Both compounds have monoclinic structure at room temperature with space group P2₁/n. A first-order structural phase transition P2₁/n → R ${\overline 3}$ has been observed in SrLaZnRuO₆ and SrLaMgRuO₆, at about 800 and 500 K, respectively, with the two phases coexisting in a temperature interval of 150 K. The temperature- and tolerance-factor-dependent phase diagram of the SrLnMRuO₆ (Ln = La, Nd and Pr; M = Zn, Co, Cu, Mg and Ni) family shows two different phase transition sequences depending on the A-site cation. The structures of the title compounds at room and high temperatures have been analyzed using the symmetry-mode decomposition approach.

Keywords: double perovskites; phase transitions; symmetry-mode analysis.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S0021889813013253/he5606sup1.cif Contains datablocks global, SrLaMgRuO6_300K, SrLaMgRuO6_773K, SrLaZnRuO6_300K, SrLaZnRuO6_1173K
	Rietveld powder data file (CIF format) https://doi.org/10.1107/S0021889813013253/he5606SrLaMgRuO6_300Ksup2.rtv Contains datablock profile1
	Rietveld powder data file (CIF format) https://doi.org/10.1107/S0021889813013253/he5606SrLaMgRuO6_773Ksup3.rtv Contains datablock profile1
	Rietveld powder data file (CIF format) https://doi.org/10.1107/S0021889813013253/he5606SrLaZnRuO6_1173Ksup4.rtv Contains datablock profile1
	Rietveld powder data file (CIF format) https://doi.org/10.1107/S0021889813013253/he5606SrLaZnRuO6_300Ksup5.rtv Contains datablock profile1

Computing details top

For all compounds, program(s) used to refine structure: FULLPROF.

(SrLaMgRuO6_300K) top

Crystal data top

LaMgO6RuSr	β = 90.04 (7)°
M_r = ?	V = 244.14 (12) Å³
Monoclinic, P2₁/n	Z = ?
Hall symbol: -P 2yn	Neutron radiation, λ = 1.594000 Å
a = 5.5832 (12) Å	T = 300 K
b = 5.5554 (15) Å	gray
c = 7.871 (3) Å	?, ? × ? × ? mm

Data collection top

Radiation source: nuclear reactor, D2B	2θ_min = 0.219°, 2θ_max = 160.169°, 2θ_step = 0.050°
Data collection mode: transmission

Refinement top

R_p = 3.774	3200 data points
R_wp = 4.850	19 parameters
R_exp = 13.012	0 restraints
R_Bragg = 9.801
χ² = NOT FOUND

Crystal data top

LaMgO6RuSr	β = 90.04 (7)°
M_r = ?	V = 244.14 (12) Å³
Monoclinic, P2₁/n	Z = ?
a = 5.5832 (12) Å	Neutron radiation, λ = 1.594000 Å
b = 5.5554 (15) Å	T = 300 K
c = 7.871 (3) Å	?, ? × ? × ? mm

Data collection top

Data collection mode: transmission

2θ_min = 0.219°, 2θ_max = 160.169°, 2θ_step = 0.050°

Refinement top

R_p = 3.774	χ² = NOT FOUND
R_wp = 4.850	3200 data points
R_exp = 13.012	19 parameters
R_Bragg = 9.801	0 restraints

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Mg1	0.00000	0.00000	0.50000	0.0061 (15)*
Ru1	0.00000	0.00000	0.00000	0.0061 (15)*
Sr1	−0.001 (5)	0.487 (4)	0.757 (7)	0.013 (2)*	0.50000
La1	−0.001 (5)	0.487 (4)	0.757 (7)	0.013 (2)*	0.50000
O1	−0.285 (7)	0.216 (7)	−0.027 (5)	0.0156 (13)*
O1_2	−0.758 (7)	0.252 (7)	0.021 (5)	0.0156 (13)*
O1_3	0.068 (5)	0.003 (6)	0.746 (7)	0.0156 (13)*

(SrLaMgRuO6_773K) top

Crystal data top

LaMgO6RuSr	V = 371.89 (4) Å³
M_r = ?	Z = ?
Trigonal, R3	Neutron radiation, λ = 1.594000 Å
Hall symbol: -R 3	T = 773 K
a = 5.6055 (3) Å	?, ? × ? × ? mm
c = 13.6667 (13) Å

Data collection top

Radiation source: nuclear reactor, D2B	Data collection mode: transmission
Ge 335 monochromator	2θ_min = 0.199°, 2θ_max = 160.149°, 2θ_step = 0.050°

Refinement top

R_p = 2.820	3200 data points
R_wp = 3.772	9 parameters
R_exp = 6.396	0 restraints
R_Bragg = 11.623
χ² = NOT FOUND

Crystal data top

LaMgO6RuSr	V = 371.89 (4) Å³
M_r = ?	Z = ?
Trigonal, R3	Neutron radiation, λ = 1.594000 Å
a = 5.6055 (3) Å	T = 773 K
c = 13.6667 (13) Å	?, ? × ? × ? mm

Data collection top

Data collection mode: transmission

2θ_min = 0.199°, 2θ_max = 160.149°, 2θ_step = 0.050°

Refinement top

R_p = 2.820	χ² = NOT FOUND
R_wp = 3.772	3200 data points
R_exp = 6.396	9 parameters
R_Bragg = 11.623	0 restraints

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Mg1	0.00000	0.00000	0.50000	0.0055 (6)*
Ru1	0.00000	0.00000	0.00000	0.0055 (6)*
Sr1	0.00000	0.00000	0.2511 (16)	0.0288 (13)*	0.50000
La1	0.00000	0.00000	0.2511 (16)	0.0288 (13)*	0.50000
O1	0.655 (4)	0.872 (2)	0.0801 (14)	0.0263 (8)*	0.99998

(SrLaZnRuO6_300K) top

Crystal data top

LaO6RuSrZn	β = 90.051 (6)°
M_r = ?	V = 247.39 (1) Å³
Monoclinic, P2₁/n	Z = ?
Hall symbol: -P 2yn	Neutron radiation, λ = 1.594000 Å
a = 5.60355 (15) Å	T = 300 K
b = 5.58739 (15) Å	?, ? × ? × ? mm
c = 7.9016 (2) Å

Data collection top

Radiation source: nuclear reactor, D2B

2θ_min = 0.151°, 2θ_max = 160.101°, 2θ_step = 0.050°

Refinement top

R_p = 3.321	3200 data points
R_wp = 4.545	31 parameters
R_exp = 5.452	0 restraints
R_Bragg = 3.482
χ² = NOT FOUND

Crystal data top

LaO6RuSrZn	β = 90.051 (6)°
M_r = ?	V = 247.39 (1) Å³
Monoclinic, P2₁/n	Z = ?
a = 5.60355 (15) Å	Neutron radiation, λ = 1.594000 Å
b = 5.58739 (15) Å	T = 300 K
c = 7.9016 (2) Å	?, ? × ? × ? mm

Data collection top

2θ_min = 0.151°, 2θ_max = 160.101°, 2θ_step = 0.050°

Refinement top

R_p = 3.321	χ² = NOT FOUND
R_wp = 4.545	3200 data points
R_exp = 5.452	31 parameters
R_Bragg = 3.482	0 restraints

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Zn1	0.00000	0.00000	0.50000	0.0037 (3)*
Ru1	0.00000	0.00000	0.00000	0.0037 (3)*
Sr1	−0.0034 (6)	0.4746 (3)	0.7518 (14)	0.0087 (3)*	0.50000
La1	−0.0034 (6)	0.4746 (3)	0.7518 (14)	0.0087 (3)*	0.50000
O1	−0.2676 (11)	0.2203 (11)	−0.0294 (7)	0.0098 (3)*
O1_2	−0.7923 (11)	0.2801 (11)	0.0371 (7)	0.0098 (3)*
O1_3	0.0666 (5)	0.0063 (5)	0.7531 (12)	0.0098 (3)*

(SrLaZnRuO6_1173K) top

Crystal data top

LaO6RuSrZn	V = 381.67 (2) Å³
M_r = ?	Z = ?
Trigonal, R3	Neutron radiation, λ = 1.594000 Å
Hall symbol: -R 3	T = 1173 K
a = 5.65403 (11) Å	?, ? × ? × ? mm
c = 13.7860 (4) Å

Data collection top

Radiation source: nuclear reactor, D2B

2θ_min = 0.190°, 2θ_max = 160.140°, 2θ_step = 0.050°

Refinement top

R_p = 3.719	3200 data points
R_wp = 5.347	10 parameters
R_exp = 5.785	0 restraints
R_Bragg = 9.602
χ² = NOT FOUND

Crystal data top

LaO6RuSrZn	V = 381.67 (2) Å³
M_r = ?	Z = ?
Trigonal, R3	Neutron radiation, λ = 1.594000 Å
a = 5.65403 (11) Å	T = 1173 K
c = 13.7860 (4) Å	?, ? × ? × ? mm

Data collection top

2θ_min = 0.190°, 2θ_max = 160.140°, 2θ_step = 0.050°

Refinement top

R_p = 3.719	χ² = NOT FOUND
R_wp = 5.347	3200 data points
R_exp = 5.785	10 parameters
R_Bragg = 9.602	0 restraints

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Zn1	0.00000	0.00000	0.50000	0.0167 (4)*
Ru1	0.00000	0.00000	0.00000	0.0167 (4)*
Sr1	0.00000	0.00000	0.2523 (9)	0.0341 (5)*	0.50000
La1	0.00000	0.00000	0.2523 (9)	0.0341 (5)*	0.50000
O1	0.6606 (16)	0.8724 (9)	0.0778 (6)	0.0467 (4)*	0.99998

Experimental details

	(SrLaMgRuO6_300K)	(SrLaMgRuO6_773K)	(SrLaZnRuO6_300K)	(SrLaZnRuO6_1173K)
Crystal data
Chemical formula	LaMgO6RuSr	LaMgO6RuSr	LaO6RuSrZn	LaO6RuSrZn
M_r	?	?	?	?
Crystal system, space group	Monoclinic, P2₁/n	Trigonal, R3	Monoclinic, P2₁/n	Trigonal, R3
Temperature (K)	300	773	300	1173
a, b, c (Å)	5.5832 (12), 5.5554 (15), 7.871 (3)	5.6055 (3), 5.6055 (3), 13.6667 (13)	5.60355 (15), 5.58739 (15), 7.9016 (2)	5.65403 (11), 5.65403 (11), 13.7860 (4)
α, β, γ (°)	90, 90.04 (7), 90	90, 90, 120	90, 90.051 (6), 90	90, 90, 120
V (Å³)	244.14 (12)	371.89 (4)	247.39 (1)	381.67 (2)
Z	?	?	?	?
Radiation type	Neutron, λ = 1.594000 Å	Neutron, λ = 1.594000 Å	Neutron, λ = 1.594000 Å	Neutron, λ = 1.594000 Å
µ (mm⁻¹)	?	?	–	–
Specimen shape, size (mm)	?, ? × ? × ?	?, ? × ? × ?	?, ? × ? × ?	?, ? × ? × ?

Data collection
Diffractometer	?	?	?	?
Specimen mounting	?	?	?	?
Data collection mode	Transmission	Transmission	?	?
Scan method	?	?	?	?
2θ values (°)	2θ_min = 0.219 2θ_max = 160.169 2θ_step = 0.050	2θ_min = 0.199 2θ_max = 160.149 2θ_step = 0.050	2θ_min = 0.151 2θ_max = 160.101 2θ_step = 0.050	2θ_min = 0.190 2θ_max = 160.140 2θ_step = 0.050

Refinement
R factors and goodness of fit	R_p = 3.774, R_wp = 4.850, R_exp = 13.012, R_Bragg = 9.801, χ² = NOT FOUND	R_p = 2.820, R_wp = 3.772, R_exp = 6.396, R_Bragg = 11.623, χ² = NOT FOUND	R_p = 3.321, R_wp = 4.545, R_exp = 5.452, R_Bragg = 3.482, χ² = NOT FOUND	R_p = 3.719, R_wp = 5.347, R_exp = 5.785, R_Bragg = 9.602, χ² = NOT FOUND
No. of data points	3200	3200	3200	3200
No. of parameters	19	9	31	10

Computer programs: FULLPROF.

Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
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Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Text
		Plain Text

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