Magnetic tunnel junctions (MTJ), a key element for magnetic random access memory, consist of two ferromagnetic thin films electrodes separated by an ultrathin insulating barrier that plays a critical role in the junction behavior. The barrier should be sufficiently thick to decouple electrodes magnetically, but the thickness at the same time has to be limited to provide effective tunneling of spin-polarized current. In the case of all-oxide epitaxial MTJs with half-metal manganite La0.67Sr0.33MnO3 (LSMO) electrodes the tunnel magnetoresistance (TMR) reaches a record value of 1900% at 4 K1. Meanwhile, the minimal thickness of epitaxial perovskite barrier (SrTiO3 or LaAlO3) has to be at least 4-6 unit cells (u.c.) to ensure magnetic decoupling of electrodes. In conjunction with a well-known problem of clamped to LSMO interface dead layer, which possesses an insulating and non-ferromagnetic behavior, the total barrier thickness becomes too large for an effective spin tunneling and TMR obtained at 300K is negligibly small.  While a unified scenario of dead layer formation still remains obscure, the mismatch strain related distortion of MnO6 octahedra due to octahedral coupling across the heterointerface are considered to be above all responsible for the deteriorated LSMO properties in the interface region. Therefore, artificial engineering the octahedral proximity effect can provide a new route for enhancing room temperature performance of all-oxide perovskite-based MTJs. It was recently shown that barrier with thickness of 1 u.c. only is able to decouple the manganite layers magnetically, if the barrier material has a rock-salt structure instead of perovskite2. Actually, embedding of an additional rock-salt monolayer between perovskite layers builds a layered structure similar to Ruddlesden-Popper (RP) phase with a general formula An+1BnO3n+1. It is known that layered manganites exhibit very intriguing anisotropic properties due to a weak electronic and magnetic coupling between perovskite blocks, allowing thus to reduce the dead layer3.  Here, we focus on the magnetic decoupling LSMO-based heterostructures interfaced via ultrathin RP layers: (SrO)2, (SrO)Sr2TiO4(SrO) and (SrO)Sr3Ti2O7(SrO) with thicknesses 0.26, 0.65 and 1.04 nm, respectively. The trilayers were fabricated by the metalorganic aerosol deposition (MAD) technique equipped with optical ellipsometry for in-situ growth monitoring. Ex-situ structural characterization was carried out by atomic force microscopy, X-ray diffractometry, and X-ray reflectivity, which revealed a perfect epitaxy with atomically smooth surface. Detailed study of interface microstructure with atomic resolution was performed by transmission electron microscopy that confirms formation of RP interfaces between manganite layers. Magnetic properties were studied with a superconducting quantum interference device (SQUID) magnetometer and the magneto-optical Kerr effect (MOKE). The most remarkable feature observed in all magnetizationfield measurements is that the curves are a superposition of two hysteresis loops with different reversal fields and moments. Two-step hysteresis suggests a weak magnetic coupling between the manganite layers interfaced via RP phases even in the case of insertion double SrO only. Therefore, by decoupling interfacial octahedra by insertion of the artificial RP interface, we are now able to decouple magnetization in manganite heterostructures to achieve independent magnetic switching at significantly reduced barrier thickness.