Table 2 Refined average crystal-structure parameters at 5 K.

From: Mixed orbital states and modulated crystal structures in La1−xCaxMnO3 deduced from synchrotron X-ray diffraction

x

0.51

0.53

0.545

0.56

0.57

0.58

0.6

a (Å)

5.4405(1)

5.4362(1)

5.4316(1)

5.4274(1)

5.4248(1)

5.4213(1)

5.4149(1)

b (Å)

7.5261(1)

7.5171(1)

7.5131(1)

7.5099(1)

7.5078(1)

7.5053(1)

7.5030(1)

c (Å)

5.4665(1)

5.4596(1)

5.4531(1)

5.4477(1)

5.4441(1)

5.4398(1)

5.4315(1)

xLa/Ca

0.0163(2)

0.0178(1)

0.0180(1)

0.0183(1)

0.0185(1)

0.0188(1)

0.0186(2)

zLa/Ca

0.0028(3)

0.0030(1)

0.0030(1)

0.0030(1)

0.0029(1)

0.0036(2)

0.0035(2)

BLa/Ca (Å2)

0.72(2)

0.87(1)

0.88(9)

0.85(1)

1.13(1)

1.21(2)

0.97(1)

BMn (Å2)

0.67(3)

0.90(2)

0.87(1)

0.92(1)

1.04(1)

1.24(2)

0.85(2)

xO1

0.481(1)

0.4857(7)

0.4851(6)

0.4846(7)

0.4866(6)

0.4861(9)

0.4860(8)

zO1

0.932(1)

0.9312(6)

0.9325(6)

0.9344(7)

0.9341(6)

0.9324(8)

0.9341(7)

BO1 (Å2)

0.5(1)

0.85(8)

0.80(7)

0.63(9)

1.01(8)

2.3(1)

0.6(1)

xO2

0.272(1)

0.2723(7)

0.2727(6)

0.2737(6)

0.2742(6)

0.2702(9)

0.2754(8)

yO2

0.032(6)

0.0330(3)

0.0320(2)

0.0324(3)

0.0323(3)

0.0398(4)

0.0331(3)

zO2

0.271(1)

0.2729(7)

0.2728(6)

0.2753(7)

0.2748(6)

0.2715(9)

0.2759(7)

BO2 (Å2)

0.8(1)

0.91(6)

0.92(5)

0.76(6)

0.84(5)

1.32(7)

0.74(7)

S400

0.31(1)

0.242(4)

0.252(4)

0.298(5)

0.251(1)

0.246(5)

0.257(5)

S040

0.232(5)

0.058(1)

0.060(1)

0.063(1)

0.055(1)

0.059(1)

0.066(1)

S004

0.46(1)

0.323(4)

0.331(4)

0.402(6)

0.325(4)

0.332(6)

0.328(6)

S220

−0.14(2)

0.070(6)

0.081(6)

0.105(9)

0.085(6)

0.051(9)

0.052(9)

S202

0.87(3)

0.56(1)

0.66(1)

0.83(2)

0.74(1)

0.71(2)

0.81(2)

S022

−0.16(1)

0.085(7)

0.102(7)

0.130(9)

0.109(7)

0.075(9)

0.103(9)

ξ

1.0

1.0

1.0

1.0

1.0

1.0

1.0

Mn-O1 × 2 (Å)

1.920(1)

1.9179(5)

1.9156(6)

1.9128(7)

1.9122(6)

1.9134(1)

1.9110(7)

Mn-O2 × 2 (Å)

1.946(8)

1.947(4)

1.948(3)

1.954(4)

1.949(3)

1.956(5)

1.946(4)

Mn-O2 × 2 (Å)

1.956(8)

1.953(4)

1.946(4)

1.940(4)

1.943(4)

1.944(5)

1.941(4)

Rp (%)

11

7.4

7.1

8.0

7.1

8.9

6.6

Rwp (%)

16

11.3

10.8

12.1

10.2

12.2

9.7

χ2 (%)

167

16.3

18.4

28.3

13.4

14.7

23.5

RB (%)

6.3

5.3

3.9

4.2

4.1

7.2

3.07

  1. Refined average crystal-structure parameters from synchrotron X-ray powder diffraction patterns of La1−xCaxMnO3 (x = 0.51, 0.53. 0.545, 0.56, 0.57, 0.58, 0.60) based on the Pnma (No. 62) space group at T = 5 K (λ = 0.50008 Å). The La, Ca and apical oxygen (O1) atoms occupy the 4c \((x,\frac{1}{4},z)\) site, the Mn atoms the 4b \((0,0,\frac{1}{2})\) site, and the equatorial oxygen (O2) atoms the general 8d(x, y, z) site. The site occupancies were kept fixed during refinement at values consistent with the nominal stoichiometry. Numbers in parentheses are statistical errors at the last significant digit. The units of Stephens parameters, SHKL, are (10−8Å−4) (Fullprof implementation).
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