Abstract. We discuss the origin of the temperature dependence of resistivity ρ observed in highly oriented LaN iO 3 thin films grown on SrT iO 3 substrate by a pulsed laser deposition technique. All the experimental data are found to collapse into a single universal curve3/2 for the entire temperature interval (20K < T < 300K) with T sf (d) being the onset temperature for triggering a resonant scattering of conduction electrons by spin fluctuations in LaN iO 3 /SrT iO 3 heterostructure.

We present measurements of resistivity ρ in highly oriented LaN iO3 films grown on LaAlO3 substrates by using a pulsed laser deposition technique. The experimental data are found to follow a universal ρ(T ) ∝ T 3/2 dependence for the entire temperature interval (20K < T < 300K). The observed behavior has been attributed to a resonant scattering of electrons on antiferromagnetic fluctuations (with a characteristic energyhω sf ≃ 2.1meV ) triggered by spin-density wave propagating through the interface boundary of LaN iO3/LaAlO3 sandwich. PACS numbers: 74.25.Fy; 74.70.-b; 74.78.Bz 1. Introduction. Even though LaN iO 3 (LNO) belongs to the nickelates family RN iO 3 (with R being a rare-earth element), it possesses unique physical properties because it does not undergo a metal-insulator transition (MIT) from paramagnetic (PM) metal to antiferromagnetic (AFM) insulator like all the other members of this family. It stays PM metal for all temperatures.However, recent investigations (see, e.g., [1-5] and further references therein) suggest that one can significantly modify LNO properties by depositing it on different substrates. This can be achieved by thickness controlled partial suppression of the charge ordering (which is believed to be responsible for manifestation of MIT in nickelates). The most interesting result of such a heterostructure engineering is probably the one that leads to appearance of a new magnetic structure, the so-called pure spin-density wave (SDW) material exhibiting properties of an AFM metal [6][7][8][9][10][11]. Such heterostructures are found to manifest very unusual properties (both magnetic and transport related). In particular, it has been successfully proven experimentally [10,11] that depositing LNO thin film on LaAlO 3 (LAO) substrate results in appearance of a rather robust AFM order inside LNO/LAO superstructure (with Neel temperature T N ≃ 100K) due to formation of SDW and concomitant charge redistribution in LNO films [7]. In this Letter we present our latest measurements of resistivity in (l00)-oriented LNO thin films deposited on (l00)-oriented LAO substrate by using the pulsed laser deposition (PLD) technique. We demonstrate that our data can be very well fitted by a rather simple law ρ(T ) = A + BT 3/2 for the entire temperature interval (20K < T < 300K). We argue that such a temperature dependence is a result of strong resonant scattering of conducting electrons on thermally excited AFM spin fluctuations (taking place inside LNO/LAO hybrid structure) which completely suppresses all the other scattering mechanisms (such as electron-phonon and electron-electron interactions).

We report the structural and transport properties of LaNiO 3 thin films prepared by pulsed laser deposition technique. To understand the effects of film thickness, lattice mismatch and grain size on transport properties, various oriented substrates were used for deposition, including single-crystalline SrLaAlO 4 (001), SrTiO 3 (100) and LaAlO 3 (100). To achieve a high quality LaNiO 3 thin films, the vital parameters (such as laser fluence, substrate temperature, oxygen pressure, and deposition time) were optimized. The best quality films are found to be well textured samples with good crystalline properties.