Try to search data obtained from ab initio (first principles) calculations with any of computational quantum chemistry packages. At least formation energy and surface energies for different planes can be simply calculated in ground state. Accounting temperature (phonons) is more complicated.

Try to look for data or refs in attached archive with 2 articles and PhD thesis:

S. Chandrasekaran et. al. - Surface termination dependent structural and magnetic properties of (0001) SmCo5 slabs.

D. Wu, PhD thesis - First-principles study on hard-soft SmCo5/Co(Fe) nanocomposite magnetic materials.

Y. Yuan et. al. - Thermodynamic modeling of the Co–Sm system

[1] Free energy of formation= -40.8kJ/mole

[2a] Reversible temperature coefficient= - 0.045 to - 0.050

[2b] Temperature coefficient of remanence (%/K)= - 0.03

[2c]Temperature coefficient of coercivity (%/K)= - 0.15 to – 0.30

[3] Surface energy value is not reported because the SmCo5 formed samples studied have slightly different % of Sm. More so , we have to be sure that there is present only a mono layer dispersion.

Then Surface energy can be calculated by rearranging Young’s equation where θ is contact angle, γ Sv, the surface energy of the solid in contact with vapor. γ lv is the free energy of the liquid vapor interface.

Cos θ=2 φ .( γ Sv/ γ lv)^0.5 -1.

φ is appxo=1.

Plot Cos θ vs 1/ (γ lv)^0.5 .

Obtain slope =2/( γ Sv)^0.5 to calculate γ Sv.

Manohar Sehgal: Can you give the values of thermodynamic properties or data of SmO, Sm2O3 and Co3O4, CoO .

[ Co3O4]

[I]ΔHf^0= -891.0 kj/mole;ΔG^0= -774.0kJ/mole; ΔS=102.5 j/mole/K; Cp=123 j/mol/K;M.pt=895.0C; Black; antiferromagnetic solid;

[II]Water insoluble, Important catalyst; p-type semi-conductor solid band gap(1.96eV); [III]Demonstrated great potential for next-generation renewable energy applications, photocatalysis and solar applications ; direct optical band gaps at 1.48 and 2.19 eV; Adopts the Normal Spinel Structure with Co2+ ions in tetrahedral interstices and Co3+ ions in the octahedral interstices of the Cubic Close-packed Lattice of oxide anions .

[IV] A comparative study of the bulk and Co3O4 (NP) parameters is given as:

(a) Both samples possess the cubic phase with a slightly lower (by 0.34%) lattice parameter for the Co3O4 NP. The average crystallite size D = 17 nm determined by x-ray diffraction and the electron microscope for the Co3O4 NP . The bulk Co3O4 has particle size in the 1–2 µm range.

(b) A Néel temperature(TN) = 30 K is determined from the analysis of the magnetic susceptibility versus temperature data for bulk Co3O4 which is in agreement with Neel temperature = 29.92 K reported from specific heat measurements. The Co3O4 NP powder exhibits a still lower TN = 26 K, possibly due to the associated finite size effects.

( c )Coercivity, Hc = 250 Oe, and exchange bias, He = −350 Oe, together with the training effect have been observed in the Co3O4 NP sample (cooled in 20 kOe). Both Hc and He approach zero as: T reaches TN.

(d)For T>TN, the χ versus T data for both samples fit the modified Curie–Weiss law (χ = χ0+C/(T+θ)). The magnitudes of C, θ and TN are used to determine the following: exchange constants J1ex = 11.7 K, J2ex = 2.3 K.

(e) magnetic moment per Co2+ ion μ = 4.27 μB for bulk Co3O4; and J1ex = 11.5 K, J2ex = 2.3 K and μ = 4.09 μB for Co3O4 NP.

(f)EPR yields a single peak at g = 2.18 in both samples but with a linewidth ΔH that is larger for the Co3O4 NP. Details of the temperature dependence of ΔH, line intensity I0, and disappearance of the EPR on approach to TN are different for the two samples because of different spin–phonon interaction and additional surface anisotropy present in Co3O4 NP.

[CoO]

( a)ΔHf^0= --237.9 kj/mole; ΔG^0= -214.2kJ kJ/mole; ΔS=53.0 j/mole/K; Cp=55.2 j/mol/K ;M.pt=1933C;

(b)Greyish or Black powder or olive-green to red crystals;Insoluble in water; readily oxidized to brown colored Co(OH)3.

(c)Cubic cF8;Fm3─ m(Adopts rock salt structure).

(d) Band gap=appxo.2.4eV(used as colat blue glass).

(e)Antiferromagnetic at low temperature with Neel temperature=291K which is much higher than Co3O4(30K).

(f) The free energy of the reaction:

Co3O4⇄3COO+12O2 It

It has been studied between 890 and 1,240 K using an e.m.f. technique. There is a phase transition in Co3O4 at 1,120±20 K which is accompanied by a large change in entropy (∼47 JK−1 mol−1 of Co3O4), and a rapid increase in unit cell volume and in electical conductivity. This is interpreted to be due to a partial change in electronic spin states in Co3 + from the spin-paired (low spin) configuration observed at room temperature to the spin-unpaired (high spin) state. The transition is probably not first order.

Sesquioxide [ Sm2O3]

(a)ΔHf^0= -- 1823.0 kJ/mole.

ΔG^0= -1734.2kJ kJ/mole.

ΔS=151.0 j/mole/K.

Cp=114.5 j/mol/K.

(b)Yellowish white powder; bcc structure

(c) An important dopant in TiO2 and glass to change their optical properties( in fact all rare earth oxides are used as dopants in TiO2).

(d )Insoluble in water; M.pt=2335C; Used in optical and infrared absorbing glass to absorb infrared radiations Also, it is a neutron absorber in nuclear power reactors.

(e) Catalyzes dehydration of acyclic primary alcohols to aldehydes and ketons.

(f) Composite SmCo5/Sm2O3 magnetic NP have been fabricated whose sizes and coercivities are very strongly affected by annealing temperatures.

(g) The crystal phase of nanocrystal is tuned by varying the surfactant in the reaction.

(h)The PL emission due to f–f electronic transition from excited states of 4G5/2 of the Sm3+ ion is observed.

(i)Magnetic susceptibility study of the nanocrystals shows that the Sm3+ ion follows the well-known Van Vleck behaviour.

[SmO]

Formed as a decay product during the reactor operation and Samarium is one of the few lanthanides that exhibit the oxidation state +2 (4f^5).

Cubic rock like ; lustrous golden-yellow compound; Obtained by reducing Sm2O3 with Sm metal at 1000 °C and pressure above 50 kbar; Lowering the pressure resulted in an incomplete reaction. No thermodynamic data are available for SmO.

I agree with Manohar Seghal

[1] Find two sets of equations for calculating ΔHf^0 and ΔGf^0 of any substance:

(A) ΔH^(reaction)^0= ΔHf(products)^0 - ΔHf(reactants)^0.

ΔGf^0= ΔHf^0-T.ΔSf^0.

Both the equations are based upon the Hess’s Law.

(B) Broido’s method is used to calculate thermodynamic parameters (kJ/mole) of a substance undergoing decomosition undergoing TGA. TGA curves which are the plots of ln [l n (1/y)] versus 1000/T where [y] is the fraction of undecomposed substance at the temperature [T]. Then:

Eact= -2.303.R. slope of the curve.

Δ H= Eact- RTd.

Δ S= Δ H/T-4.576 log T/K -47.22.

Δ G= Δ H-T. Δ S.

R (gas constant), K= - ln [l n (1/y)];Td (temperature of decomosition).

Higer the value of Eact, the more is the thermal stability of the complex.

[II]But here the first set of eqations has a limitation because it is virtually impossible to obtain Sm2O3/SmO in the pure state.So you have to perform the TGA.

[III] I cite a few lines of the following paper to emphasize this fact in bold letters for your perusal:

F. Meyer-Liautaud, C.H. Allibert, R. Castanet

Journal of the Less Common Metals (J Less Common Met)

Journal of the Less Common Metals 01/1987; 127:243-250.

Several intermetallic compounds exist in the composition range 10–22 at.% Sm(Sm2Co17, SmCo5, Sm2Co7). BUT THEIR PREPARATION AS SINGLE PHASE-SPECIMENS IS VERY DIFFICULT. In order to determine the enthalpies of formation of these compounds, measurements were carried out on four alloys containing respectively 12.9 at.% Sm, 16.4 at.% Sm, 17 at.% Sm and 19.8 at.% Sm, annealed in the temperature range 950–1100 °C. The compositions of the phases present in each specimen were deduced from the characterization of the measured alloys by scanning electron microscopy, electron microanalysis and X-ray diffraction.The heats of formation were deduced from solution calorimetry in molten tin. The variation of the experimental results as a function of the samarium content enabled the enthalpy of formation of SmCo5 ( − 40.8 kJ mol−1) to be determined. The same ΔHf value as determined for the phase quenched from 950 °C was measured for SmCo5 kept at room temperature after very slow cooling. This result did not confirm the eutectoid decomposition previously reported for SmCo5.The extrapolation of the measured values for the higher and lower samarium contents leads to the evaluation of the enthalpies of formation of Sm2Co17 (−152 kJ mol−1) and Sm2Co7 (−99kJ mol−1).

From the literature survey ,I could find a few values:

Mean Reversible temperature coefficient of :

SmCo5(Sintered) = - 0.04 C

SmCo(Bonded) = - 0.04C

SmCo(Sintered) = -0.12 to - 0.16C