Inflation-protected Treasury securities (TIPS) may be a good option for an IRA account. The principal value of a TIPS increases along with inflation, allowing investors to generate a positive real return (after inflation). Putting municipal bonds in an IRA doesn't make much sense. The great benefit of municipal bonds is their fiscal advantage.
The interest paid on these bonds is exempt from federal taxes and, if you choose a municipal bond issued by your state of residence, the interest is also exempt from state taxes. However, the interest paid on investments within an IRA is already tax-exempt, so including a municipal bond in an IRA negates its advantages. And because municipal bonds tend to pay lower interest than non-tax-exempt bonds, you'll lose some of the interest you could get with another type of bond. Treasury bonds, sometimes referred to as T-bonds, are debt instruments issued by the United States government.
When you buy a Treasury bond, you're basically lending money to the government. In exchange, the government agrees to pay you interest twice a year during the life of the bond. Once the bond expires, the government will return the money you lent to you. Because they are backed by the full faith and credit of the United States Government, Treasury bonds are one of the safest investments you can buy.
Including a tax-managed investment fund within an IRA doesn't make sense for the same reason that municipal bonds are a poor investment in an IRA.